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1 /* |
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2 ** 2001 September 15 |
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3 ** |
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4 ** The author disclaims copyright to this source code. In place of |
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5 ** a legal notice, here is a blessing: |
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6 ** |
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7 ** May you do good and not evil. |
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8 ** May you find forgiveness for yourself and forgive others. |
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9 ** May you share freely, never taking more than you give. |
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10 ** |
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11 ************************************************************************* |
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12 ** This file contains C code routines that are called by the parser |
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13 ** to handle UPDATE statements. |
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14 ** |
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15 ** $Id: update.c,v 1.184 2008/09/01 21:59:43 shane Exp $ |
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16 */ |
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17 #include "sqliteInt.h" |
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18 |
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19 #ifndef SQLITE_OMIT_VIRTUALTABLE |
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20 /* Forward declaration */ |
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21 static void updateVirtualTable( |
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22 Parse *pParse, /* The parsing context */ |
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23 SrcList *pSrc, /* The virtual table to be modified */ |
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24 Table *pTab, /* The virtual table */ |
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25 ExprList *pChanges, /* The columns to change in the UPDATE statement */ |
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26 Expr *pRowidExpr, /* Expression used to recompute the rowid */ |
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27 int *aXRef, /* Mapping from columns of pTab to entries in pChanges */ |
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28 Expr *pWhere /* WHERE clause of the UPDATE statement */ |
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29 ); |
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30 #endif /* SQLITE_OMIT_VIRTUALTABLE */ |
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31 |
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32 /* |
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33 ** The most recently coded instruction was an OP_Column to retrieve the |
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34 ** i-th column of table pTab. This routine sets the P4 parameter of the |
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35 ** OP_Column to the default value, if any. |
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36 ** |
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37 ** The default value of a column is specified by a DEFAULT clause in the |
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38 ** column definition. This was either supplied by the user when the table |
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39 ** was created, or added later to the table definition by an ALTER TABLE |
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40 ** command. If the latter, then the row-records in the table btree on disk |
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41 ** may not contain a value for the column and the default value, taken |
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42 ** from the P4 parameter of the OP_Column instruction, is returned instead. |
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43 ** If the former, then all row-records are guaranteed to include a value |
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44 ** for the column and the P4 value is not required. |
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45 ** |
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46 ** Column definitions created by an ALTER TABLE command may only have |
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47 ** literal default values specified: a number, null or a string. (If a more |
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48 ** complicated default expression value was provided, it is evaluated |
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49 ** when the ALTER TABLE is executed and one of the literal values written |
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50 ** into the sqlite_master table.) |
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51 ** |
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52 ** Therefore, the P4 parameter is only required if the default value for |
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53 ** the column is a literal number, string or null. The sqlite3ValueFromExpr() |
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54 ** function is capable of transforming these types of expressions into |
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55 ** sqlite3_value objects. |
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56 */ |
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57 void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){ |
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58 if( pTab && !pTab->pSelect ){ |
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59 sqlite3_value *pValue; |
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60 u8 enc = ENC(sqlite3VdbeDb(v)); |
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61 Column *pCol = &pTab->aCol[i]; |
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62 VdbeComment((v, "%s.%s", pTab->zName, pCol->zName)); |
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63 assert( i<pTab->nCol ); |
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64 sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, |
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65 pCol->affinity, &pValue); |
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66 if( pValue ){ |
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67 sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM); |
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68 } |
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69 } |
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70 } |
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71 |
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72 /* |
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73 ** Process an UPDATE statement. |
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74 ** |
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75 ** UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL; |
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76 ** \_______/ \________/ \______/ \________________/ |
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77 * onError pTabList pChanges pWhere |
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78 */ |
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79 void sqlite3Update( |
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80 Parse *pParse, /* The parser context */ |
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81 SrcList *pTabList, /* The table in which we should change things */ |
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82 ExprList *pChanges, /* Things to be changed */ |
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83 Expr *pWhere, /* The WHERE clause. May be null */ |
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84 int onError /* How to handle constraint errors */ |
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85 ){ |
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86 int i, j; /* Loop counters */ |
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87 Table *pTab; /* The table to be updated */ |
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88 int addr = 0; /* VDBE instruction address of the start of the loop */ |
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89 WhereInfo *pWInfo; /* Information about the WHERE clause */ |
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90 Vdbe *v; /* The virtual database engine */ |
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91 Index *pIdx; /* For looping over indices */ |
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92 int nIdx; /* Number of indices that need updating */ |
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93 int iCur; /* VDBE Cursor number of pTab */ |
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94 sqlite3 *db; /* The database structure */ |
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95 int *aRegIdx = 0; /* One register assigned to each index to be updated */ |
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96 int *aXRef = 0; /* aXRef[i] is the index in pChanges->a[] of the |
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97 ** an expression for the i-th column of the table. |
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98 ** aXRef[i]==-1 if the i-th column is not changed. */ |
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99 int chngRowid; /* True if the record number is being changed */ |
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100 Expr *pRowidExpr = 0; /* Expression defining the new record number */ |
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101 int openAll = 0; /* True if all indices need to be opened */ |
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102 AuthContext sContext; /* The authorization context */ |
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103 NameContext sNC; /* The name-context to resolve expressions in */ |
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104 int iDb; /* Database containing the table being updated */ |
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105 int j1; /* Addresses of jump instructions */ |
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106 int okOnePass; /* True for one-pass algorithm without the FIFO */ |
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107 |
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108 #ifndef SQLITE_OMIT_TRIGGER |
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109 int isView; /* Trying to update a view */ |
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110 int triggers_exist = 0; /* True if any row triggers exist */ |
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111 #endif |
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112 int iBeginAfterTrigger; /* Address of after trigger program */ |
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113 int iEndAfterTrigger; /* Exit of after trigger program */ |
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114 int iBeginBeforeTrigger; /* Address of before trigger program */ |
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115 int iEndBeforeTrigger; /* Exit of before trigger program */ |
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116 u32 old_col_mask = 0; /* Mask of OLD.* columns in use */ |
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117 u32 new_col_mask = 0; /* Mask of NEW.* columns in use */ |
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118 |
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119 int newIdx = -1; /* index of trigger "new" temp table */ |
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120 int oldIdx = -1; /* index of trigger "old" temp table */ |
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121 |
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122 /* Register Allocations */ |
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123 int regRowCount = 0; /* A count of rows changed */ |
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124 int regOldRowid; /* The old rowid */ |
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125 int regNewRowid; /* The new rowid */ |
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126 int regData; /* New data for the row */ |
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127 |
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128 sContext.pParse = 0; |
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129 db = pParse->db; |
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130 if( pParse->nErr || db->mallocFailed ){ |
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131 goto update_cleanup; |
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132 } |
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133 assert( pTabList->nSrc==1 ); |
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134 |
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135 /* Locate the table which we want to update. |
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136 */ |
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137 pTab = sqlite3SrcListLookup(pParse, pTabList); |
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138 if( pTab==0 ) goto update_cleanup; |
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139 iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema); |
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140 |
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141 /* Figure out if we have any triggers and if the table being |
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142 ** updated is a view |
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143 */ |
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144 #ifndef SQLITE_OMIT_TRIGGER |
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145 triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges); |
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146 isView = pTab->pSelect!=0; |
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147 #else |
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148 # define triggers_exist 0 |
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149 # define isView 0 |
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150 #endif |
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151 #ifdef SQLITE_OMIT_VIEW |
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152 # undef isView |
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153 # define isView 0 |
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154 #endif |
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155 |
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156 if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){ |
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157 goto update_cleanup; |
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158 } |
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159 if( sqlite3ViewGetColumnNames(pParse, pTab) ){ |
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160 goto update_cleanup; |
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161 } |
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162 aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol ); |
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163 if( aXRef==0 ) goto update_cleanup; |
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164 for(i=0; i<pTab->nCol; i++) aXRef[i] = -1; |
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165 |
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166 /* If there are FOR EACH ROW triggers, allocate cursors for the |
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167 ** special OLD and NEW tables |
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168 */ |
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169 if( triggers_exist ){ |
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170 newIdx = pParse->nTab++; |
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171 oldIdx = pParse->nTab++; |
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172 } |
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173 |
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174 /* Allocate a cursors for the main database table and for all indices. |
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175 ** The index cursors might not be used, but if they are used they |
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176 ** need to occur right after the database cursor. So go ahead and |
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177 ** allocate enough space, just in case. |
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178 */ |
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179 pTabList->a[0].iCursor = iCur = pParse->nTab++; |
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180 for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ |
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181 pParse->nTab++; |
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182 } |
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183 |
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184 /* Initialize the name-context */ |
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185 memset(&sNC, 0, sizeof(sNC)); |
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186 sNC.pParse = pParse; |
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187 sNC.pSrcList = pTabList; |
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188 |
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189 /* Resolve the column names in all the expressions of the |
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190 ** of the UPDATE statement. Also find the column index |
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191 ** for each column to be updated in the pChanges array. For each |
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192 ** column to be updated, make sure we have authorization to change |
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193 ** that column. |
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194 */ |
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195 chngRowid = 0; |
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196 for(i=0; i<pChanges->nExpr; i++){ |
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197 if( sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){ |
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198 goto update_cleanup; |
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199 } |
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200 for(j=0; j<pTab->nCol; j++){ |
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201 if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){ |
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202 if( j==pTab->iPKey ){ |
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203 chngRowid = 1; |
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204 pRowidExpr = pChanges->a[i].pExpr; |
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205 } |
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206 aXRef[j] = i; |
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207 break; |
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208 } |
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209 } |
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210 if( j>=pTab->nCol ){ |
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211 if( sqlite3IsRowid(pChanges->a[i].zName) ){ |
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212 chngRowid = 1; |
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213 pRowidExpr = pChanges->a[i].pExpr; |
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214 }else{ |
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215 sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName); |
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216 goto update_cleanup; |
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217 } |
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218 } |
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219 #ifndef SQLITE_OMIT_AUTHORIZATION |
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220 { |
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221 int rc; |
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222 rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName, |
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223 pTab->aCol[j].zName, db->aDb[iDb].zName); |
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224 if( rc==SQLITE_DENY ){ |
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225 goto update_cleanup; |
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226 }else if( rc==SQLITE_IGNORE ){ |
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227 aXRef[j] = -1; |
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228 } |
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229 } |
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230 #endif |
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231 } |
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232 |
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233 /* Allocate memory for the array aRegIdx[]. There is one entry in the |
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234 ** array for each index associated with table being updated. Fill in |
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235 ** the value with a register number for indices that are to be used |
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236 ** and with zero for unused indices. |
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237 */ |
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238 for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){} |
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239 if( nIdx>0 ){ |
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240 aRegIdx = sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx ); |
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241 if( aRegIdx==0 ) goto update_cleanup; |
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242 } |
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243 for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){ |
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244 int reg; |
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245 if( chngRowid ){ |
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246 reg = ++pParse->nMem; |
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247 }else{ |
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248 reg = 0; |
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249 for(i=0; i<pIdx->nColumn; i++){ |
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250 if( aXRef[pIdx->aiColumn[i]]>=0 ){ |
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251 reg = ++pParse->nMem; |
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252 break; |
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253 } |
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254 } |
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255 } |
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256 aRegIdx[j] = reg; |
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257 } |
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258 |
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259 /* Allocate a block of register used to store the change record |
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260 ** sent to sqlite3GenerateConstraintChecks(). There are either |
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261 ** one or two registers for holding the rowid. One rowid register |
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262 ** is used if chngRowid is false and two are used if chngRowid is |
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263 ** true. Following these are pTab->nCol register holding column |
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264 ** data. |
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265 */ |
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266 regOldRowid = regNewRowid = pParse->nMem + 1; |
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267 pParse->nMem += pTab->nCol + 1; |
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268 if( chngRowid ){ |
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269 regNewRowid++; |
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270 pParse->nMem++; |
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271 } |
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272 regData = regNewRowid+1; |
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273 |
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274 |
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275 /* Begin generating code. |
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276 */ |
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277 v = sqlite3GetVdbe(pParse); |
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278 if( v==0 ) goto update_cleanup; |
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279 if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); |
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280 sqlite3BeginWriteOperation(pParse, 1, iDb); |
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281 |
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282 #ifndef SQLITE_OMIT_VIRTUALTABLE |
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283 /* Virtual tables must be handled separately */ |
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284 if( IsVirtual(pTab) ){ |
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285 updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef, |
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286 pWhere); |
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287 pWhere = 0; |
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288 pTabList = 0; |
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289 goto update_cleanup; |
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290 } |
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291 #endif |
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292 |
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293 /* Start the view context |
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294 */ |
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295 if( isView ){ |
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296 sqlite3AuthContextPush(pParse, &sContext, pTab->zName); |
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297 } |
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298 |
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299 /* Generate the code for triggers. |
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300 */ |
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301 if( triggers_exist ){ |
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302 int iGoto; |
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303 |
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304 /* Create pseudo-tables for NEW and OLD |
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305 */ |
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306 sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol); |
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307 sqlite3VdbeAddOp2(v, OP_OpenPseudo, oldIdx, 0); |
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308 sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol); |
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309 sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0); |
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310 |
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311 iGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0); |
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312 addr = sqlite3VdbeMakeLabel(v); |
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313 iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v); |
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314 if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab, |
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315 newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){ |
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316 goto update_cleanup; |
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317 } |
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318 iEndBeforeTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0); |
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319 iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v); |
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320 if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, |
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321 newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){ |
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322 goto update_cleanup; |
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323 } |
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324 iEndAfterTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0); |
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325 sqlite3VdbeJumpHere(v, iGoto); |
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326 } |
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327 |
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328 /* If we are trying to update a view, realize that view into |
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329 ** a ephemeral table. |
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330 */ |
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331 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) |
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332 if( isView ){ |
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333 sqlite3MaterializeView(pParse, pTab, pWhere, iCur); |
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334 } |
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335 #endif |
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336 |
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337 /* Resolve the column names in all the expressions in the |
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338 ** WHERE clause. |
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339 */ |
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340 if( sqlite3ResolveExprNames(&sNC, pWhere) ){ |
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341 goto update_cleanup; |
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342 } |
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343 |
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344 /* Begin the database scan |
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345 */ |
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346 sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid); |
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347 pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, |
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348 WHERE_ONEPASS_DESIRED); |
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349 if( pWInfo==0 ) goto update_cleanup; |
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350 okOnePass = pWInfo->okOnePass; |
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351 |
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352 /* Remember the rowid of every item to be updated. |
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353 */ |
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354 sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid); |
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355 if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0); |
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356 |
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357 /* End the database scan loop. |
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358 */ |
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359 sqlite3WhereEnd(pWInfo); |
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360 |
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361 /* Initialize the count of updated rows |
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362 */ |
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363 if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ |
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364 regRowCount = ++pParse->nMem; |
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365 sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount); |
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366 } |
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367 |
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368 if( !isView && !IsVirtual(pTab) ){ |
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369 /* |
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370 ** Open every index that needs updating. Note that if any |
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371 ** index could potentially invoke a REPLACE conflict resolution |
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372 ** action, then we need to open all indices because we might need |
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373 ** to be deleting some records. |
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374 */ |
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375 if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); |
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376 if( onError==OE_Replace ){ |
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377 openAll = 1; |
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378 }else{ |
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379 openAll = 0; |
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380 for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ |
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381 if( pIdx->onError==OE_Replace ){ |
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382 openAll = 1; |
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383 break; |
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384 } |
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385 } |
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386 } |
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387 for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ |
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388 if( openAll || aRegIdx[i]>0 ){ |
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389 KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx); |
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390 sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb, |
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391 (char*)pKey, P4_KEYINFO_HANDOFF); |
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392 assert( pParse->nTab>iCur+i+1 ); |
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393 } |
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394 } |
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395 } |
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396 |
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397 /* Jump back to this point if a trigger encounters an IGNORE constraint. */ |
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398 if( triggers_exist ){ |
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399 sqlite3VdbeResolveLabel(v, addr); |
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400 } |
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401 |
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402 /* Top of the update loop */ |
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403 if( okOnePass ){ |
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404 int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid); |
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405 addr = sqlite3VdbeAddOp0(v, OP_Goto); |
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406 sqlite3VdbeJumpHere(v, a1); |
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407 }else{ |
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408 addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0); |
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409 } |
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410 |
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411 if( triggers_exist ){ |
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412 int regRowid; |
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413 int regRow; |
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414 int regCols; |
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415 |
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416 /* Make cursor iCur point to the record that is being updated. |
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417 */ |
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418 sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid); |
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419 |
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420 /* Generate the OLD table |
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421 */ |
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422 regRowid = sqlite3GetTempReg(pParse); |
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423 regRow = sqlite3GetTempReg(pParse); |
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424 sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid); |
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425 if( !old_col_mask ){ |
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426 sqlite3VdbeAddOp2(v, OP_Null, 0, regRow); |
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427 }else{ |
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428 sqlite3VdbeAddOp2(v, OP_RowData, iCur, regRow); |
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429 } |
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430 sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, regRow, regRowid); |
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431 |
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432 /* Generate the NEW table |
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433 */ |
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434 if( chngRowid ){ |
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435 sqlite3ExprCodeAndCache(pParse, pRowidExpr, regRowid); |
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436 }else{ |
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437 sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid); |
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438 } |
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439 regCols = sqlite3GetTempRange(pParse, pTab->nCol); |
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440 for(i=0; i<pTab->nCol; i++){ |
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441 if( i==pTab->iPKey ){ |
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442 sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i); |
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443 continue; |
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444 } |
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445 j = aXRef[i]; |
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446 if( new_col_mask&((u32)1<<i) || new_col_mask==0xffffffff ){ |
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447 if( j<0 ){ |
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448 sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regCols+i); |
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449 sqlite3ColumnDefault(v, pTab, i); |
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450 }else{ |
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451 sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr, regCols+i); |
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452 } |
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453 }else{ |
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454 sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i); |
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455 } |
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456 } |
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457 sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRow); |
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458 if( !isView ){ |
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459 sqlite3TableAffinityStr(v, pTab); |
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460 sqlite3ExprCacheAffinityChange(pParse, regCols, pTab->nCol); |
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461 } |
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462 sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol); |
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463 /* if( pParse->nErr ) goto update_cleanup; */ |
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464 sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRow, regRowid); |
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465 sqlite3ReleaseTempReg(pParse, regRowid); |
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466 sqlite3ReleaseTempReg(pParse, regRow); |
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467 |
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468 sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger); |
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469 sqlite3VdbeJumpHere(v, iEndBeforeTrigger); |
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470 } |
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471 |
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472 if( !isView && !IsVirtual(pTab) ){ |
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473 /* Loop over every record that needs updating. We have to load |
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474 ** the old data for each record to be updated because some columns |
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475 ** might not change and we will need to copy the old value. |
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476 ** Also, the old data is needed to delete the old index entries. |
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477 ** So make the cursor point at the old record. |
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478 */ |
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479 sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid); |
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480 |
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481 /* If the record number will change, push the record number as it |
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482 ** will be after the update. (The old record number is currently |
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483 ** on top of the stack.) |
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484 */ |
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485 if( chngRowid ){ |
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486 sqlite3ExprCode(pParse, pRowidExpr, regNewRowid); |
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487 sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid); |
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488 } |
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489 |
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490 /* Compute new data for this record. |
|
491 */ |
|
492 for(i=0; i<pTab->nCol; i++){ |
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493 if( i==pTab->iPKey ){ |
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494 sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i); |
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495 continue; |
|
496 } |
|
497 j = aXRef[i]; |
|
498 if( j<0 ){ |
|
499 sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i); |
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500 sqlite3ColumnDefault(v, pTab, i); |
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501 }else{ |
|
502 sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i); |
|
503 } |
|
504 } |
|
505 |
|
506 /* Do constraint checks |
|
507 */ |
|
508 sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid, |
|
509 aRegIdx, chngRowid, 1, |
|
510 onError, addr); |
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511 |
|
512 /* Delete the old indices for the current record. |
|
513 */ |
|
514 j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid); |
|
515 sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx); |
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516 |
|
517 /* If changing the record number, delete the old record. |
|
518 */ |
|
519 if( chngRowid ){ |
|
520 sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0); |
|
521 } |
|
522 sqlite3VdbeJumpHere(v, j1); |
|
523 |
|
524 /* Create the new index entries and the new record. |
|
525 */ |
|
526 sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, |
|
527 aRegIdx, chngRowid, 1, -1, 0); |
|
528 } |
|
529 |
|
530 /* Increment the row counter |
|
531 */ |
|
532 if( db->flags & SQLITE_CountRows && !pParse->trigStack){ |
|
533 sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1); |
|
534 } |
|
535 |
|
536 /* If there are triggers, close all the cursors after each iteration |
|
537 ** through the loop. The fire the after triggers. |
|
538 */ |
|
539 if( triggers_exist ){ |
|
540 sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger); |
|
541 sqlite3VdbeJumpHere(v, iEndAfterTrigger); |
|
542 } |
|
543 |
|
544 /* Repeat the above with the next record to be updated, until |
|
545 ** all record selected by the WHERE clause have been updated. |
|
546 */ |
|
547 sqlite3VdbeAddOp2(v, OP_Goto, 0, addr); |
|
548 sqlite3VdbeJumpHere(v, addr); |
|
549 |
|
550 /* Close all tables */ |
|
551 for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ |
|
552 if( openAll || aRegIdx[i]>0 ){ |
|
553 sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0); |
|
554 } |
|
555 } |
|
556 sqlite3VdbeAddOp2(v, OP_Close, iCur, 0); |
|
557 if( triggers_exist ){ |
|
558 sqlite3VdbeAddOp2(v, OP_Close, newIdx, 0); |
|
559 sqlite3VdbeAddOp2(v, OP_Close, oldIdx, 0); |
|
560 } |
|
561 |
|
562 /* |
|
563 ** Return the number of rows that were changed. If this routine is |
|
564 ** generating code because of a call to sqlite3NestedParse(), do not |
|
565 ** invoke the callback function. |
|
566 */ |
|
567 if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){ |
|
568 sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1); |
|
569 sqlite3VdbeSetNumCols(v, 1); |
|
570 sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC); |
|
571 } |
|
572 |
|
573 update_cleanup: |
|
574 sqlite3AuthContextPop(&sContext); |
|
575 sqlite3DbFree(db, aRegIdx); |
|
576 sqlite3DbFree(db, aXRef); |
|
577 sqlite3SrcListDelete(db, pTabList); |
|
578 sqlite3ExprListDelete(db, pChanges); |
|
579 sqlite3ExprDelete(db, pWhere); |
|
580 return; |
|
581 } |
|
582 |
|
583 #ifndef SQLITE_OMIT_VIRTUALTABLE |
|
584 /* |
|
585 ** Generate code for an UPDATE of a virtual table. |
|
586 ** |
|
587 ** The strategy is that we create an ephemerial table that contains |
|
588 ** for each row to be changed: |
|
589 ** |
|
590 ** (A) The original rowid of that row. |
|
591 ** (B) The revised rowid for the row. (note1) |
|
592 ** (C) The content of every column in the row. |
|
593 ** |
|
594 ** Then we loop over this ephemeral table and for each row in |
|
595 ** the ephermeral table call VUpdate. |
|
596 ** |
|
597 ** When finished, drop the ephemeral table. |
|
598 ** |
|
599 ** (note1) Actually, if we know in advance that (A) is always the same |
|
600 ** as (B) we only store (A), then duplicate (A) when pulling |
|
601 ** it out of the ephemeral table before calling VUpdate. |
|
602 */ |
|
603 static void updateVirtualTable( |
|
604 Parse *pParse, /* The parsing context */ |
|
605 SrcList *pSrc, /* The virtual table to be modified */ |
|
606 Table *pTab, /* The virtual table */ |
|
607 ExprList *pChanges, /* The columns to change in the UPDATE statement */ |
|
608 Expr *pRowid, /* Expression used to recompute the rowid */ |
|
609 int *aXRef, /* Mapping from columns of pTab to entries in pChanges */ |
|
610 Expr *pWhere /* WHERE clause of the UPDATE statement */ |
|
611 ){ |
|
612 Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */ |
|
613 ExprList *pEList = 0; /* The result set of the SELECT statement */ |
|
614 Select *pSelect = 0; /* The SELECT statement */ |
|
615 Expr *pExpr; /* Temporary expression */ |
|
616 int ephemTab; /* Table holding the result of the SELECT */ |
|
617 int i; /* Loop counter */ |
|
618 int addr; /* Address of top of loop */ |
|
619 int iReg; /* First register in set passed to OP_VUpdate */ |
|
620 sqlite3 *db = pParse->db; /* Database connection */ |
|
621 const char *pVtab = (const char*)pTab->pVtab; |
|
622 SelectDest dest; |
|
623 |
|
624 /* Construct the SELECT statement that will find the new values for |
|
625 ** all updated rows. |
|
626 */ |
|
627 pEList = sqlite3ExprListAppend(pParse, 0, |
|
628 sqlite3CreateIdExpr(pParse, "_rowid_"), 0); |
|
629 if( pRowid ){ |
|
630 pEList = sqlite3ExprListAppend(pParse, pEList, |
|
631 sqlite3ExprDup(db, pRowid), 0); |
|
632 } |
|
633 assert( pTab->iPKey<0 ); |
|
634 for(i=0; i<pTab->nCol; i++){ |
|
635 if( aXRef[i]>=0 ){ |
|
636 pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr); |
|
637 }else{ |
|
638 pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName); |
|
639 } |
|
640 pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0); |
|
641 } |
|
642 pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0); |
|
643 |
|
644 /* Create the ephemeral table into which the update results will |
|
645 ** be stored. |
|
646 */ |
|
647 assert( v ); |
|
648 ephemTab = pParse->nTab++; |
|
649 sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0)); |
|
650 |
|
651 /* fill the ephemeral table |
|
652 */ |
|
653 sqlite3SelectDestInit(&dest, SRT_Table, ephemTab); |
|
654 sqlite3Select(pParse, pSelect, &dest); |
|
655 |
|
656 /* Generate code to scan the ephemeral table and call VUpdate. */ |
|
657 iReg = ++pParse->nMem; |
|
658 pParse->nMem += pTab->nCol+1; |
|
659 sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0); |
|
660 addr = sqlite3VdbeCurrentAddr(v); |
|
661 sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg); |
|
662 sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1); |
|
663 for(i=0; i<pTab->nCol; i++){ |
|
664 sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i); |
|
665 } |
|
666 sqlite3VtabMakeWritable(pParse, pTab); |
|
667 sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVtab, P4_VTAB); |
|
668 sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr); |
|
669 sqlite3VdbeJumpHere(v, addr-1); |
|
670 sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0); |
|
671 |
|
672 /* Cleanup */ |
|
673 sqlite3SelectDelete(db, pSelect); |
|
674 } |
|
675 #endif /* SQLITE_OMIT_VIRTUALTABLE */ |
|
676 |
|
677 /* Make sure "isView" gets undefined in case this file becomes part of |
|
678 ** the amalgamation - so that subsequent files do not see isView as a |
|
679 ** macro. */ |
|
680 #undef isView |