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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-3CCA6503-54DA-5558-85DC-93A22A81F565" xml:lang="en"><title>Reading |
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13 to Memory</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>This tutorial describes how to copy data from the table to a memory location. </p> |
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15 <section><title>Introduction</title> <p>You can avoid making a local copy |
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16 of the data by directly writing the retrieved data into a memory location. |
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17 This can be achieved by copying to an object of the <xref href="GUID-5CD07A27-E3ED-3273-A560-680501468C91.dita"><apiname>TPtrC</apiname></xref> class. |
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18 For more details on copying data to a buffer see <xref href="GUID-72511204-FC90-54AA-9E2E-833318020318.dita">Reading |
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19 to a Buffer</xref>. </p> </section> |
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20 <section><title>Basic procedure</title> <p>The high level steps to copy the |
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21 data retrieved from a table to a memory location are shown below: </p> <ol id="GUID-E2B78DD5-841E-526B-A6BE-C8ACCF79FA6D"> |
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22 <li id="GUID-7F20C95F-0225-58A9-92EE-86DF83AD9C2B"><p>Configure your SQL statement. </p> </li> |
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23 <li id="GUID-F4A653E4-571E-52D0-960E-98B995666B75"><p>Copy to memory. </p> </li> |
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24 </ol> </section> |
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25 <section><title>Detailed steps</title> <p><b>Configure your SQL statement</b> </p> <p>Instantiate |
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26 an object of the <xref href="GUID-0176BF07-DF94-3259-8F90-DE030E35CE9A.dita"><apiname>RSqlStatement</apiname></xref> class and declare the required |
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27 variables as shown. </p> <codeblock id="GUID-188E5840-729F-5F63-9498-086B8EE5C6D3" xml:space="preserve">RSqlStatement myStatement; |
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28 TInt err;</codeblock> <p><b>Copy to memory</b> </p><p>To retrieve all the |
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29 entries, use a loop. |
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30 </p><p/><p>1. Instantiate an object of the <xref href="GUID-E884CBEB-A5B5-308E-8E88-9A1543184899.dita"><apiname>TPtrc</apiname></xref> class. |
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31 This object may be used to reference constant strings or data. </p><codeblock xml:space="preserve">... |
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32 while((err = myStatement.Next()) == KSqlAtRow) |
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33 { |
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34 TPtrC myData; |
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35 TInt err; |
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36 </codeblock><p>2 Read the data into the specified memory location..</p><codeblock xml:space="preserve"> err = myStatement.ColumnBinary(myColumnIndex,myData); |
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37 // process data |
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38 }</codeblock> </section> |
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39 <section><title>See also</title> <p> <xref href="GUID-F36E5978-29FC-57E8-8A45-2003E7767193.dita">Querying |
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40 a Database</xref> </p> <p> <xref href="GUID-CCB9C61B-FB28-5CD9-A366-4A9584097897.dita">Inserting |
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41 a Row into a Table</xref> </p> <p> <xref href="GUID-3ACF6C11-A9CC-517C-8C7D-578F41F3DDF7.dita">Deleting |
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42 Rows from a Table</xref> </p> <p> <xref href="GUID-72511204-FC90-54AA-9E2E-833318020318.dita">Reading |
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43 to a Buffer</xref> </p> <p>Reading to memory - This document </p> <p> <xref href="GUID-183280EE-0C57-54FE-8ABB-E1CC3BDE525B.dita">Reading to a Data Stream</xref> </p> <p> <xref href="GUID-B9A3B17E-BDEB-5F66-968C-080335A721AC.dita">Writing to a Data Stream</xref> </p> <p> <xref href="GUID-C474376E-1766-5781-B5BF-3786C5B4D72E.dita">Performing Scalar Queries</xref> </p> </section> |
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44 </conbody></concept> |