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通用的数据库中间库

            <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><STRONG>1.</STRONG> 
            SQLAPI++ supports four types for working with 
            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>
            <TABLE border=1 cellPadding=5 width=100%>
                
                <TR>
                    <TD>
                        <P><STRONG>When using OCI8:</STRONG></P></TD>
                    <TD>
                        <P><EM>SA_dtLongBinary</EM> &lt;= &gt; LONG RAW<BR 
                        ><EM>SA_dtLongChar</EM> &lt;= &gt; LONG<BR><EM>SA_dtBLob</EM> &lt;= 
                        &gt; BLOB, FILE<BR><EM>SA_dtCLob </EM>&lt;= &gt; CLOB</P></TD></TR>
                <TR>
                    <TD>
                        <P><STRONG>When using OCI7:</STRONG></P></TD>
                    <TD>
                        <P><EM>SA_dtLongBinary</EM> &lt;= &gt; LONG RAW<BR 
                        ><EM>SA_dtLongChar</EM> &lt;= &gt; LONG<BR><EM>SA_dtBLob</EM> = &gt; 
                        LONG RAW<BR><EM>SA_dtCLob </EM>= &gt; LONG</P></TD></TR>
			</TABLE></P>
            <P>
            For more details see <A href="../HowTo/blobs.html">How To - Working with Long or Lob(CLob, BLob) data</A></P>
            <P><STRONG>2.</STRONG> Binding Lob(CLob, BLob) 
            data when working with <STRONG>Oracle</STRONG>
            server has some differences from others (see <A 
            href="../HowTo/bind.html">How To - Binding input parameters</A>). 
            It's necessary for a name of bind variable to be the same as the 
            column name it associated with.</P>
            <P><FONT face=System>Ex.:&nbsp;&nbsp;&nbsp;&nbsp; Update TEST set <FONT 
            color=maroon face="">FBLOB = :fblob</FONT> 
            where FKEY = 
               'KEY'</FONT> </P>
            <P>Therefore, it's impossible to bind Lob(CLob, 
            BLob) data to <STRONG>Oracle</STRONG>      
                database by position. </P>
            <P>
            For more details see <A href="../HowTo/bind.html">How To - Binding input parameters</A>.   
			</P>
            <P>&nbsp;</P>
            
            <H3><A 
            name="Returning output parameters">Returning output 
            parameters</A>  </H3>
            <P>     
              In <STRONG>Oracle</STRONG>
              output parameters are 
            available immediately after calling 
            <A 
            href="../OnLineDoc/Command_Execute.html" >SACommand::Execute</A>.</P>
            <P>SQLAPI++ Library automatically creates <A href="../OnLineDoc/Param.html" >SAParam</A>
            object to represent function 
            return value. You can refer to this <A href="../OnLineDoc/Param.html" >SAParam</A> 
            object using SQLAPI++ predefined 
            name <STRONG>&quot;RETURN_VALUE&quot;</STRONG>.</P>
            <P>For more details see <A 
            href="../OnLineDoc/Command_Execute.html">SACommand::Execute</A>, 
            <A href="../OnLineDoc/Param_Usage.html">SAParam 
            object</A>, <A 
            href="../HowTo/return_param.html">How To - Returning Output Parameters</A>.</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>obreak</STRONG> function with <STRONG>Oracle 7</STRONG>     (OCI7) to cancel a 
            query. To get more details see <STRONG>obreak</STRONG> function description in 
            <STRONG>Oracle</STRONG>     
            documentation.</p>
            <p>SQLAPI++ calls <STRONG>OCIBreak</STRONG> function with <STRONG>Oracle 8</STRONG>     (OCI8) to cancel a 
            query. To get more details see <STRONG>OCIBreak</STRONG> function description in 
            <STRONG>Oracle</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 and command 
            options</A>   </H3>
            <P>A server specific option can be related with a command or with a 
            connection. A connection related option must be specified in a&nbsp; 
            <A href="../OnLineDoc/Connection.html" >SAConnection</A>
            object. A command related option 
            may be specified in either <A href="../OnLineDoc/Connection.html" >SAConnection</A>
            object or <A href="../OnLineDoc/Command_Usage.html" >SACommand</A> 
            object. </P>
            <P>Specific options for <STRONG>Oracle</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</FONT>&nbsp;</STRONG></P>
					</TD>
				<TD>
                    <P>
                        <STRONG><FONT 
                        color=white face="">Description</FONT>  </STRONG></P>  
                    </TD>
             </TR>   
             <TR>
                 <TD>  <STRONG><P align=center> 
                          <STRONG>UseAPI</STRONG></P></STRONG></TD>
                 <TD>
					<P>
                    Forces SQLAPI++ Library to use 
                        directly OCI7 or OCI8 API.
                    <BR>
                        <STRONG>Connection 
                        related.</STRONG><BR>Valid values: 
                        &quot;OCI7&quot;, &quot;OCI8&quot; and 
                        &quot;OCIAuto&quot;.
                    <BR>
                        Default 
                        value: &quot;OCIAuto&quot;. In this case SQLAPI++ tries 
                        to connect to Oracle using OCI8 first. If it fails it 
                        tries to connect using OCI7.</P> 
                    </TD></TR>       
             <TR>
                 <TD>  <STRONG><P align=center> 
                          <STRONG>PreFetchRows</STRONG></P></STRONG></TD>
                 <TD>
					<P>
                    Forces SQLAPI++ Library to fetch 
 
                    rows in bulk, rather than 
                        retrieving records one by one.
                    <BR>
                        <STRONG>Command 
                        related.</STRONG> Should be specified 
                        before command execution.<BR>Valid 
                        values: String containing number of rows 
                        in the fetch 
                        buffer.
                    <BR>
                          Default value: &quot;1&quot;.</P> 
                    </TD></TR>       
                  </TBODY></TABLE>   </P>
            <P>For more details see <A href="../OnLineDoc/Command_setOption.html" >SACommand::setOption</A>, 
            <A href="../OnLineDoc/Connection_setOption.html" >SAConnection::setOption</A>.</P>
            <P>&nbsp;</P>
            
            <H3><A name="Getting native Oracle API">Getting 
            native Oracle API</A>   </H3>
            <P>You can call client specific API functions 
            which are not directly supported by SQLAPI++ Library. <A 
            href="../OnLineDoc/Connection_NativeAPI.html">SAConnection::NativeAPI</A> 
            method returns a pointer to the set of native API functions 
            available for <STRONG>Oracle</STRONG>       
             . To use the database API directly you have to downcast 
            this <STRONG>saAPI</STRONG> 
            pointer to the appropriate type and use its 
            implementation-specific members. The following table shows what type 
            cast you have to make and what additional header file you have to 
            include to work with <STRONG>Oracle</STRONG>
              API. Note that using appropriate type casting depends 
            on an API version (that generally mean that you have to explicitly 
            check client version before casting, see <A 
            href="../OnLineDoc/Connection_ClientVersion.html">SAConnection::ClientVersion</A> 
            method). </P>
            <P>
            <TABLE border=1 cellPadding=5 width=100%>
                
                <TR bgColor=#000094>
                    <TD width=30>
                        <P><STRONG><FONT color=white face="">DBMS client</FONT> 
                        </STRONG></P></TD>
                    <TD style="WIDTH: 300px" width=300>
                        <P><STRONG><FONT color=white face="">Type casting</FONT> 
                        </STRONG></P></TD>
                    <TD>
                        <P><STRONG><FONT color=white face="">Additional 
                        <BR>include 
                        file</FONT> </STRONG></P></TD></TR>