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1 /* |
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2 * Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: Adaptation layer to SQLite database* |
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15 */ |
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16 |
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17 #ifndef __MDSSQLITECONNECTION_H__ |
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18 #define __MDSSQLITECONNECTION_H__ |
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19 |
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20 #include <e32base.h> |
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21 #include <sqldb.h> |
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22 |
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23 #include "mdssqlrow.h" |
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24 |
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25 |
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26 // FORWARD DECLARATION |
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27 class RMdsStatement; |
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28 |
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29 |
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30 |
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31 // CLASS DECLARATION |
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32 /** |
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33 * Class represents methods to communication with SQLite database API. |
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34 */ |
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35 NONSHARABLE_CLASS(CMdSSqLiteConnection): public CBase |
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36 { |
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37 public: // Constructors and destructor |
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38 |
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39 /** |
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40 * Two-phased constructor. |
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41 * @param |
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42 * @return |
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43 */ |
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44 static CMdSSqLiteConnection* NewL(); |
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45 |
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46 /** |
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47 * Two-phased constructor. |
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48 * @param |
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49 * @return |
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50 */ |
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51 static CMdSSqLiteConnection* NewLC(); |
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52 |
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53 /** |
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54 * Destructor. |
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55 */ |
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56 virtual ~CMdSSqLiteConnection(); |
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57 |
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58 /** |
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59 * Deletes database from disc |
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60 * |
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61 * @param aName name of database or NULL to delete default one |
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62 */ |
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63 static void DeleteDb( TDesC16* aName = NULL ); |
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64 |
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65 private: // Private constructors |
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66 |
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67 /** |
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68 * CSqLiteConnection. |
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69 * C++ default constructor. |
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70 */ |
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71 CMdSSqLiteConnection(); |
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72 |
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73 /** |
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74 * ConstructL. |
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75 * 2nd phase constructor. |
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76 */ |
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77 void ConstructL(); |
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78 |
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79 public: // Methods from CMdSSqLiteConnection |
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80 |
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81 /** |
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82 * Open database (creates if doesn't exist) |
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83 * @param aFile Database filename and path |
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84 */ |
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85 void OpenDbL( const TDesC& aDbFileName ); |
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86 |
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87 /** |
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88 * Close opened database |
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89 */ |
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90 void CloseDb(); |
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91 |
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92 /** |
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93 * Execute sql command (not a query) |
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94 * @param aCommand SQL clause to be executed (can include wildcards) |
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95 * @param aVariables data that will replace wildcards in the command |
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96 * @return KErrNone, if successful, otherwise one of the error codes. |
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97 */ |
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98 TInt ExecuteL( const TDesC& aCommand, |
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99 const RRowData& aVariables, |
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100 RMdsStatement* aStatement = NULL ); |
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101 |
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102 /** |
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103 * Prepare and execute sql query |
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104 * @param aQuery the SQL query to perform |
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105 * @param aStatement ptr to statement id, which must be initially NULL. |
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106 * The statement can be used for executing the same query several |
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107 * times with different variables. Note that finally the statement |
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108 * must be terminated. |
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109 * @param aVariables data that will replace wildcards in the command |
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110 */ |
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111 void ExecuteQueryL( const TDesC& aQuery, |
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112 RMdsStatement& aStatement, |
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113 const RRowData& aVariables ); |
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114 |
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115 /** |
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116 * Get next row in query |
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117 * @param aQuery ID of the query |
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118 * @param aRow specifies target for the data to receive |
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119 * @return true if there are more rows available |
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120 */ |
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121 TBool NextRowL( RMdsStatement& aQuery, RRowData& aRow ); |
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122 |
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123 /** |
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124 * Update the current row in query |
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125 * (in case some of the datatypes need to change) |
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126 * @param aQuery ID of the query |
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127 * @param aRow specifies target for the data to receive |
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128 * @return true if there are more rows available |
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129 */ |
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130 void CurrentRowL( const RMdsStatement& aQuery, RRowData& aRow ); |
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131 |
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132 /** |
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133 * terminates a running query or execution loop |
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134 * @param aStatement ID of the statement |
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135 */ |
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136 void Terminate( RMdsStatement& aQuery ); |
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137 |
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138 /** |
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139 * Rolls back the transaction explicitly |
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140 * - possibility to receive leave |
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141 * eliminates actions on destructor. |
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142 */ |
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143 void TransactionBeginL(); |
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144 |
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145 /** |
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146 * Resets the transaction |
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147 * (does not commit or rollback or do anything) |
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148 */ |
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149 void TransactionCommitL(); |
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150 |
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151 /** |
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152 * error within transaction |
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153 */ |
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154 void TransactionRollbackL(); |
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155 |
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156 /** |
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157 * Returns DB filename of the connection. |
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158 */ |
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159 const TDesC& DbFileName() const; |
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160 |
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161 void EnableTransaction( TBool aEnable, RMdsStatement& aQuery ); |
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162 |
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163 protected: // Personal methods |
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164 |
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165 /** |
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166 * Binds variables in SQLite interface |
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167 * @param aStatement SQLite statement handle |
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168 * @param aVariables the list of variables to bind |
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169 */ |
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170 void DoBindL( RSqlStatement& aStatement, const RRowData& aVariables ); |
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171 |
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172 /** |
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173 * Reads row column variables from SQLite interface |
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174 * @param aStatement SQLite statement handle |
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175 * @param aRow the row buffer where to read the column data |
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176 */ |
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177 void ColumnsL( const RSqlStatement& aStatement, RRowData& aRow ); |
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178 |
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179 /** |
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180 * Saves trace of last SQL error and leaves. |
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181 * @param aFailedCommand a C-style representation of the failed SqLite command (for logging) |
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182 * @param aSqliteError the error reported by sqlite |
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183 */ |
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184 void TraceAndLeaveL( const TDesC& aFailedCommand, TInt aSqliteError ); |
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185 |
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186 private: // Member data |
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187 |
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188 /** |
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189 * iMdeSqlDb, interface to the Sqlite database. |
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190 */ |
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191 RSqlDatabase iMdeSqlDb; |
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192 |
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193 HBufC* iDbFileName; |
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194 |
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195 TBool iEnableTransaction; |
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196 |
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197 TBool iTransactionOngoing; |
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198 |
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199 RMdsStatement* iNotFinishFindQuery; |
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200 }; |
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201 |
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202 const TInt KDoNothing = 99; |
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203 |
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204 /** |
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205 * Transaction class |
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206 */ |
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207 class RMdSTransaction |
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208 { |
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209 public: |
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210 |
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211 /** |
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212 * constructor |
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213 * creates a transaction to given connection |
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214 */ |
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215 inline RMdSTransaction( CMdSSqLiteConnection& aConnection ) |
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216 : iConnection( aConnection ) |
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217 { |
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218 TRAP( iErrorState, iConnection.TransactionBeginL() ); |
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219 } |
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220 |
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221 /** |
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222 * cleanup method (from TBase) |
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223 * according to status does Commit/Rollback/nothing |
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224 */ |
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225 inline void Close() |
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226 { |
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227 if ( iErrorState != KErrNone ) |
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228 { |
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229 TRAP( iErrorState, iConnection.TransactionRollbackL() ); |
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230 } |
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231 } |
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232 |
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233 /** |
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234 * Commits the transaction explicitly |
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235 * - possibility to receive leave |
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236 * eliminates actions on destructor. |
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237 */ |
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238 inline void CommitL() |
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239 { |
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240 iConnection.TransactionCommitL(); |
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241 Reset(); |
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242 } |
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243 |
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244 /** |
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245 * Rolls back the transaction explicitly |
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246 * - possibility to receive leave |
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247 * eliminates actions on destructor. |
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248 */ |
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249 inline void RollbackL() |
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250 { |
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251 iConnection.TransactionRollbackL(); |
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252 Reset(); |
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253 } |
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254 |
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255 /** |
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256 * Resets the transaction |
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257 * (does not commit or rollback or do anything) |
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258 */ |
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259 inline void Reset() |
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260 { |
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261 iErrorState = KDoNothing; |
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262 } |
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263 |
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264 /** |
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265 * error within transaction |
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266 */ |
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267 inline TInt Error() |
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268 { |
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269 return iErrorState; |
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270 } |
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271 |
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272 protected: |
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273 |
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274 |
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275 /** the connection */ |
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276 CMdSSqLiteConnection& iConnection; |
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277 |
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278 /** transaction begin error */ |
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279 TInt iErrorState; |
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280 }; |
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281 |
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282 /** |
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283 * An open statement stack helper |
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284 * ensures a statement gets terminated |
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285 */ |
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286 class RMdsStatement |
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287 { |
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288 friend class CMdSSqLiteConnection; |
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289 public: |
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290 /** constructor */ |
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291 inline RMdsStatement( ) |
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292 : iPrepared( EFalse ) |
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293 { |
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294 } |
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295 |
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296 inline void RMdsStatement::Close() |
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297 { |
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298 iStatement.Close(); |
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299 } |
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300 private: |
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301 |
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302 /** SQL statement */ |
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303 RSqlStatement iStatement; |
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304 |
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305 /** if statement was already prepared */ |
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306 TBool iPrepared; |
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307 }; |
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308 |
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309 /* |
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310 |
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311 how to use the statement stack helper: |
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312 |
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313 { |
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314 RMdsStatement st( connection ); |
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315 CleanupClosePushL( st ); |
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316 connection.ExecuteL( clause, variables1, st ); // prepared and executed |
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317 connection.ExecuteL( clause, variables2, st ); // executed normally |
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318 CleanupStack::PopAndDestroy( st ); |
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319 } // statement automatically terminated |
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320 |
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321 { |
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322 RMdsStatement st( connection ); |
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323 CleanupClosePushL( st ); |
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324 connection.ExecuteQueryL( query, st, variables1 ); |
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325 connection.NextRowL( st, results1 ); // fetch a result row |
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326 connection.ExecuteQueryL( query, st, variables2 ); // query with different variable set |
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327 connection.NextRowL( st, results2 ); // fetch another resut row |
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328 CleanupStack::PopAndDestroy( st ); |
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329 } // statement automatically terminated |
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330 |
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331 */ |
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332 |
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333 #endif // __MDSSQLITECONNECTION_H__ |