7 Nokia Corporation - initial contribution. |
7 Nokia Corporation - initial contribution. |
8 Contributors: |
8 Contributors: |
9 --> |
9 --> |
10 <!DOCTYPE concept |
10 <!DOCTYPE concept |
11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
12 <concept xml:lang="en" id="GUID-118C8F84-2BB3-5F60-B6AB-22F0F1B3349E"><title>Types of rowset</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>Database application programs use a <keyword>rowset</keyword>, which maintains a <keyword>cursor</keyword> on a current row within that set. The rowset provides an abstract interface, two types are provided:</p> <ul><li id="GUID-87C3A645-D3F9-5D16-8B4C-CA3FE80AA7D3"><p>a table is an entire table in a database. Row ordering is either undefined, or by one of the table’s indexes. Fast key-based retrieval using an index can be performed on a table. The table is encapsulated in the derived class <codeph>RDbTable</codeph>.</p> </li> <li id="GUID-BC628D8C-BCC4-50AF-B1E3-93428CDB8506"><p>an SQL view is a rowset generated by an <keyword>SQL</keyword> query on a database, currently restricted to a single table. Cursor navigation is implemented by evaluating the view as necessary. Since evaluation may be expensive, a pre-evaluation window may be specified, allowing the rowset to be evaluated once and navigated quickly. The desired window is described by the <codeph>TDbWindow</codeph> class. Rowsets can also be evaluated in steps. The SQL view is encapsulated in the derived class <codeph>RDbView</codeph>. </p> </li> </ul> </conbody></concept> |
12 <concept id="GUID-118C8F84-2BB3-5F60-B6AB-22F0F1B3349E" xml:lang="en"><title>Types |
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13 of rowset</title><shortdesc>Describes the types of rowset available to you.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>Database application programs use a <keyword>rowset</keyword>, which maintains |
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15 a <keyword>cursor</keyword> on a current row within that set. The rowset provides |
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16 an abstract interface, two types are provided:</p> |
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17 <ul> |
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18 <li id="GUID-87C3A645-D3F9-5D16-8B4C-CA3FE80AA7D3"><p>a table is an entire |
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19 table in a database. Row ordering is either undefined, or by one of the table’s |
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20 indexes. Fast key-based retrieval using an index can be performed on a table. |
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21 The table is encapsulated in the derived class <codeph>RDbTable</codeph>.</p> </li> |
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22 <li id="GUID-BC628D8C-BCC4-50AF-B1E3-93428CDB8506"><p>an SQL view is a rowset |
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23 generated by an <keyword>SQL</keyword> query on a database, currently restricted |
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24 to a single table. Cursor navigation is implemented by evaluating the view |
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25 as necessary. Since evaluation may be expensive, a pre-evaluation window may |
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26 be specified, allowing the rowset to be evaluated once and navigated quickly. |
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27 The desired window is described by the <codeph>TDbWindow</codeph> class. Rowsets |
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28 can also be evaluated in steps. The SQL view is encapsulated in the derived |
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29 class <codeph>RDbView</codeph>. </p> </li> |
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30 </ul> |
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31 </conbody></concept> |