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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-5E522208-E8ED-5E95-946C-5D87CF303F1D" xml:lang="en"><title>Storing

    13 Messages in SQL Database</title><shortdesc>This document explains how to define the header structure of messages

    14 before storing them in the SQL database and lists the advantages of doing

    15 so. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    16 <section id="GUID-FC18D7D2-4B90-548F-A3C7-AAA32DEAB058"><title>Header

    17 structure</title> <p>The header structure of messages is specific to each

    18 Message Type Module (MTM). The Messaging framework provides a generic interface

    19 to store and access the header information. </p> <p>MTM developers use the <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>CMsvHeaderStore</apiname></xref> API to create a specific

    20 header table and specify their message header structure to the Message Server. </p> <p>The <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>CMsvHeaderStore::CreateStoreL()</apiname></xref> function

    21 creates a header table. Before creating a header table for your MTM, you should

    22 check whether the table already exists, by calling the <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>DoesStoreExistsL()</apiname></xref> function. </p> <p> <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname> TCommonHeaderField</apiname></xref> is the enumeration

    23 defining the following standard message header fields: </p> <ul>

    24 <li id="GUID-B3C53A00-1430-57DB-BD3C-F0F63C105E87"><p> <codeph>EFrom</codeph> –

    25 ‘From’ field of the message header </p> </li>

    26 <li id="GUID-44C7345E-911E-5392-ACC4-D3B6A6F15D78"><p> <codeph>EBCC</codeph> –

    27 ‘BCC’ field of the message header </p> </li>

    28 <li id="GUID-45F46F10-9922-5646-8A4B-F00759B1BE72"><p> <codeph>ETo</codeph> –

    29 ‘To’ field of the message header </p> </li>

    30 <li id="GUID-5F7CA59A-CD5F-573C-91A0-148442CCCC5A"><p> <codeph>ECC</codeph> –

    31 ‘CC’ field of the message header. </p> </li>

    32 <li id="GUID-CBEE41C2-0197-533D-AD0B-A76EC2506FE3"><p> <codeph>ESubject</codeph> –

    33 ‘Subject’ field of the message header. </p> </li>

    34 </ul> <p>To add specific fields to the header table, call the <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>AddFieldL()</apiname></xref> function. </p> <p> <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>CEmailAccounts</apiname></xref> is the API provided by the

    35 email client MTM. This class creates, loads, saves and deletes email accounts.

    36 When creating the email account, the client MTM has to provide the header

    37 structure through the <xref href="GUID-0D95F395-B164-36C7-B745-177DDC8F17C5.dita"><apiname>CMsvHeaderStore</apiname></xref> API

    38 to pass to the Messaging framework. The framework will then create the header

    39 for the account. </p> </section>

    40 <section><title>Advantages of SQL message storage</title> <p>The message headers

    41 are stored in an SQL database, which provides the following advantages: </p> <ul>

    42 <li id="GUID-A1C20DCD-625E-5732-85E9-082FD488D398"><p>robustness of mail storage </p> </li>

    43 <li id="GUID-527ED804-E6E3-5833-BB10-EDD5E5D2EC81"><p>quick processing of

    44 the frequently-required header data </p> </li>

    45 <li id="GUID-E5E62B12-07EA-58A1-BC8A-389C17F43A21"><p>support for search-sort

    46 operations </p> </li>

    47 <li id="GUID-39CB6C7D-AA08-5F7D-BC8B-ACCE227D6C5F"><p>increased performance

    48 of the Message Server. </p> </li>

    49 </ul> </section>

    50 </conbody><related-links>

    51 <link href="GUID-9A3E0279-4F87-594D-A987-66DC77F408A0.dita"><linktext>Creating

    52 and Reading Email Messages in Chunks</linktext></link>

    53 <link href="GUID-6FE94423-9563-5F31-95EB-504479144B05.dita"><linktext>Storing and

    54 Restoring Email Messages in                 Chunks</linktext></link>

    55 </related-links></concept>