sqlbase.html

通用的数据库中间库

                <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>SQLBase</STRONG> server in the following way:</P>
            <P> <STRONG 
            >SA_ReadUncommitted</STRONG> = SQLILRL    
            ('RL')<BR><STRONG> SA_ReadCommitted</STRONG> = 
  
  SQLILCS  
              
             ('CS')<BR><STRONG> SA_RepeatableRead</STRONG> = SQLILRR     
            ('RR')<BR><STRONG> SA_Serializable</STRONG> = 
  
  SQLILRO    
              
            ('RO')</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;  LONG VARCHAR<BR><EM>SA_dtLongChar</EM> 
            &lt;=  
            &gt;  LONG VARCHAR<BR 
            ><EM>SA_dtBLob</EM> =  &gt;  LONG 
            VARCHAR<BR><EM>SA_dtCLob 
            </EM>=&gt; LONG VARCHAR</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>If <STRONG>SQLBase</STRONG> stored procedure returns only 
            one row of output parameters (the most common case), you can 
            get output parameters' values immediately after calling <A 
            href="../OnLineDoc/Command_Execute.html" 
            >SACommand::Execute</A> 
            using appropriate <A 
            href="../OnLineDoc/Param.html">SAParam</A> objects.</p>
            <P>       
                       
             In <STRONG>SQLBase</STRONG> stored procedures can also return 
            several rows of output parameters. In this case      
                      SQLBase 
            returns them as a result set and you can 
            fetch them row by row using <A 
            href="../OnLineDoc/Command_FetchNext.html">SACommand::FetchNext</A>
             method after calling 
            <A href="../OnLineDoc/Command_Execute.html">SACommand::Execute</A>          
            method.</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>sqlcan</STRONG> function to cancel a query. To get more details 
            see <STRONG>sqlcan</STRONG> function 
            description in <STRONG>SQLBase</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> SQLBase</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>
                        <P align=center><STRONG><STRONG><STRONG>
            <STRONG>       
                 SQPPCX </STRONG></STRONG></STRONG> 
                        </STRONG></P></TD>
                    <TD>
                        <P>Controls cursor-context 
                        preservation. For more information see SQLBase documentation. <BR 
            ><STRONG>Command 
                        related.</STRONG>
            <BR>Valid values: 
                        &quot;off&quot; and &quot;on&quot;.
            <BR>Default
                         value: see SQLBase documentation.</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 SQLBase API">Getting native SQLBase 
            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>SQLBase</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>SQLBase</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>
                <TR>
                    <TD><STRONG>
                        <p><STRONG>SQLBase 6</STRONG></p>  </STRONG></TD>
                    <TD>
                        <P>Cast the result to <STRONG>class sb6API</STRONG>:</P>
                        <P><FONT face=System>saAPI *pResult = con.NativeAPI();<BR>sb6API *p_sb6API = (sb6API 
                        *)pResult;</FONT></P></TD>
                    <TD>
                        <P><STRONG>#include &lt;sbAPI.h&gt;</STRONG></P></TD></TR>