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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

</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

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

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

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

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

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

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

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

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

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

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

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

operations </p> </li>

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

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

</ul> </section>

</conbody><related-links>

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

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

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

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