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能够连接各种数据库的API

            to use when establishing the connection.<BR><EM>sPassword.</EM>&nbsp;&nbsp;&nbsp; A string containing a 
            password to use when establishing the connection.<BR><EM>eSAClient.</EM>&nbsp;&nbsp;&nbsp; Optional. One of the 
            following values from <STRONG>SAClient_t</STRONG> enum:
            <UL>
                <LI><STRONG>SA_MySQL_Client</STRONG>&nbsp;&nbsp;&nbsp; 
                MySQL client.
                <LI><STRONG>SA_Client_NotSpecified</STRONG>&nbsp;&nbsp;&nbsp;&nbsp; 
                Used by default if <EM>eSAClient</EM>parameter is 
                omitted.&nbsp; You can use this default value only if you have 
                call <A 
                href="../OnLineDoc/Connection_setClient.html">SAConnection::setClient</A> 
                method with <STRONG>SA_MySQL_Client</STRONG> 
                constant before.</LI> 
            </UL>     
                <P>The SQLAPI++ Library requires MySQL C API 
            version 3.23.x or higher.</P>
            <P>For more details see <A 
            href="../HowTo/connect.html">How To - Connecting to databases</A>, <A 
            href="../OnLineDoc/Connection_Usage.html">SAConnection object</A>, <A 
            href="../OnLineDoc/Connection_Connect.html">SAConnection::Connect</A>.</P>
            <P>&nbsp;</P>
            
            <H3><A 
            name="Transaction isolation levels">Transaction isolation 
            levels</A>  </H3>
            <P >
                SQL-92 defines four isolation levels, all of 
            which are supported by SQLAPI++:</P>
                <UL>
                <LI >
                    Read uncommitted (the lowest level where 
                transactions are isolated just enough to ensure that physically 
                corrupt data is not read) 
                    <LI >
                        Read committed 
                        <LI>Repeatable read<LI>Serializable (the highest level, where 
                transactions are completely isolated from one another) </LI></UL><P>SQLAPI++ maps different isolation levels on 
                <STRONG>
                    MySQL</STRONG> server in the following way:</P>
                    <P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
                        <STRONG 
            >SA_ReadUncommitted</STRONG> =  
            'READ UNCOMMITTED'<BR><STRONG > 
                        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SA_ReadCommitted</STRONG> = 
             'READ COMMITTED' <BR 
                        ><STRONG 
            >&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
            SA_RepeatableRead</STRONG> = 
  
   'REPEATABLE READ'<BR 
            >
                        <STRONG>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SA_Serializable</STRONG> = 
             'SERIALIZABLE'</P>
            <P>For more details see<A href="../OnLineDoc/Connection_setIsolationLevel.html" > 
                        SAConnection::setIsolationLevel</A>. </P>
            <P>&nbsp;</P>
            
            <H3><A 
            name="Working with Long or Lob(CLob, BLob) data">Working with Long or Lob(CLob, 
            BLob) data</A>    </H3>
            <P> 
            SQLAPI++ supports four types for working with 
            Long or Lob(CLob, BLob) data:</P>
            <P>
            <TABLE border=1 cellPadding=1 cellSpacing=1 style="WIDTH: 100%" 
            width=100%>
                
                <TR bgColor=navy>
                    <TD><FONT color=white 
                        style="BACKGROUND-COLOR: #000080">Name</FONT></TD>
                    <TD><FONT color=white 
                        style="BACKGROUND-COLOR: #000080">C 
                        enum constant</FONT></TD>
                </TR>
                <TR>
                    <TD>LongBinary</TD>
                    <TD>SA_dtLongBinary</TD>
                </TR>
                <TR>
                    <TD>LongChar</TD>
                    <TD>SA_dtLongChar</TD>
                </TR>
                <TR>
                    <TD>BLob (Binary Large object)</TD>
                    <TD>SA_dtBLob</TD>
                </TR>
                <TR>
                    <TD>CLob (Character Large object)</TD>
                    <TD>SA_dtCLob</TD>
                </TR></TABLE></P>
            <P>The table below shows how SQLAPI++ data 
            types correspond with servers original data types:</P>
            <P><EM>SA_dtLongBinary</EM> &lt;= &gt; BLOB<BR><EM>SA_dtLongChar</EM> &lt;= &gt; TEXT<BR 
            ><EM>SA_dtBLob</EM> = &gt; 
            BLOB<BR><EM>SA_dtCLob 
            </EM>=&gt; TEXT</EM></P>
            <P>
            For more details see <A href="../HowTo/blobs.html">How To - Working with Long or Lob(CLob, BLob) data</A></P>
            <P>&nbsp;</P>
            
            <H3><A 
            name="Returning output parameters">Returning output 
            parameters</A>  </H3>
            <p><STRONG> MySQL</STRONG> 
            server does not support 
               returning output parameters from stored procedures.</p>
            <P>&nbsp;</P>
            
            <H3><A name="Cancelling queries">Cancelling 
            queries</A> </H3>
            <P>Using <A href="../OnLineDoc/Command_Cancel.html" >SACommand::Cancel</A> method you 
            can cancel the following types of processing on a statement:</P>
            <UL type=disc>
                <LI>A function running asynchronously on 
                the statement.<BR>
                <LI>A function running on the statement on 
                another thread. </LI></UL>
            <p>SQLAPI++ calls <STRONG>mysql_kill</STRONG> function to cancel a query, and then calls 
            <STRONG>mysql_ping</STRONG> function to restore connection with server. To get more 
            details see <STRONG>mysql_kill</STRONG> and <STRONG>mysql_ping</STRONG> functions 
            description in <STRONG>MySQL</STRONG> 
            documentation.</p>
            <P>For more details see <A href="../OnLineDoc/Command_Cancel.html" >SACommand::Cancel</A>.</P>
            <P>&nbsp;</P>
            
            <H3><A 
            name="Connection and command options">Connection, command, parameter and field 
            options</A> 
            </H3>
            <P>A server specific option can relate to a 
            connection, command,&nbsp; parameter or field. We recommend you 
            specify each option in an appropriate object, although it is 
            possible to specify them in the parental object as well. In that 
            case the option affects all the child objects. </P>
            <P>A connection related option must be specified 
            in a&nbsp; <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object. </P>
            <P>A command related option may be specified in 
            either <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object or <A href="../OnLineDoc/Command.html">SACommand</A> 
            object. If it is specified 
            in <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object it affects all 
            the commands on that connection. </P>
            <P>A parameter related option may be specified in 
            <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object, <A href="../OnLineDoc/Command.html">SACommand</A> 
            object or <A href="../OnLineDoc/Param.html">SAParam</A> 
            object. If it is specified in <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object it affects all 
            the commands and therefore all the parameters on that connection. If 
            it is specified in <A href="../OnLineDoc/Command.html">SACommand</A> 
            object it affects all the 
            parameters on that command. </P>
            <P>A field related option may be specified in 
            <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object, <A href="../OnLineDoc/Command.html">SACommand</A> 
            object or <A href="../OnLineDoc/Field.html">SAField</A> 
            object. If it is specified in 
            <A href="../OnLineDoc/Connection.html">SAConnection</A> 
            object it affects all 
            the commands and therefore all the fields on that connection. If it 
            is specified in <A href="../OnLineDoc/Command.html">SACommand</A> 
            object it affects all the 
            fields on that command. </P>
            <P>Specific options for <STRONG>MySQL</STRONG>:</P>
            <P>
            <TABLE border=1 cellPadding=5 width=100%>
                <TBODY>
                <TR bgColor=#000094>
                    <TD width=17%>
                        <P><STRONG><FONT 
                        color=white face="">Option name / 
                        Scope</FONT>&nbsp; </STRONG></P></TD>
                    <TD>
                        <P><STRONG><FONT 
                        color=white face="">Description</FONT> </STRONG></P></TD></TR>
                <TR>
                    <TD>
                        <P>
                    <STRONG>
                        HandleResult</STRONG></P>
                        <P align=center>Command related. Should be specified 
                        before command execution.
                    <STRONG>
                        </STRONG></P></TD>
                    <TD>Determines whether the result 
                        set will be stored in a temporary table or local bufer 
                        on a client (it allows to open several result sets 
                        simultaneously in one transaction), or it will be read 
                        row by row directly from the server (somewhat faster and 
                        uses much less memory). For more information see MySQL 
                        documentation (<EM>mysql_store_result()</EM> and 
                        <EM>mysql_use_result()</EM>       
                                 
                           functions).<BR>   
                             <BR><EM>Valid values</EM>: 
                        &quot;use&quot; to force SQLAPI++ to call 
                        <EM>mysql_use_result()</EM> function, &quot;store&quot;