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**SQLCALLBACK**(//entity//, //SQLCallBackInterface//, [//flag//])

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| **SQLCALLBACK** | Register or unregister a SQLCallBackInterface. |
| //entity// | The label of a FILE or VIEW. |
| //SQLCallBackInterface// | The label of the interface that implements the SQLCallBackInterface. The method of the SQLCallbackInterface (ExecutingCode) is called just before the SQL statement is passed to the SQL server for execution. |
| //flag// | An integer constant, variable, EQUATE, or expression that indicates whether or not to unregister an interface accociated with a FILE or VIEW. A value of one (1 or TRUE) unregisters the interface. If omitted, the interface is registered with the //entity.// |

The **SQLCallback** method registers a callback interface with the specified entity. The methods of the registered interface are called whenever a file operation is done. Multiple interfaces can be registered with an entity.

To unregister an interface, set the //flag //to TRUE. Any registered interfaces must be unregistered before the object that implements the interface is removed.

**Implementation:** This function is only supported by the SQL drivers.

**Example:**

**PROGRAM**

**    MAP**

**    END**

**    INCLUDE ('FILECB.INC'),ONCE**

**!Data file**

**People      FILE,DRIVER('TOPSPEED'),PRE(PEO),CREATE,BINDABLE,THREAD**

**KeyId        KEY(PEO:Id),NOCASE,OPT**

**KeyLastName  KEY(PEO:LastName),DUP,NOCASE**

**Record       RECORD,PRE()**

**Id            LONG**

**FirstName     STRING(30)**

**LastName      STRING(30)**

**Gender        LONG**

**             END**

**            END**

**!DataFile**

**SQLFile  FILE,DRIVER('MSSQL'),OWNER('(local),clarion,sa,;'),NAME('sptesttable')**

**Record    RECORD**

**Id         LONG**

**          END**

**         END**

**!LogFile**

**LogFile  FILE,DRIVER('BASIC','/ALWAYSQUOTE=OFF /COMMA=1,1'),CREATE,NAME('logfile.txt')**

**Record    RECORD**

**Operation  STRING(200)**

**          END**

**         END**

**!FileCallback implementation**

**FCB CLASS,IMPLEMENTS(FileCallBackInterface),IMPLEMENTS(SQLCallBackInterface)**

**    END**

**    CODE**

**    CALLBACK(People,FCB.FileCallBackInterface)             !Register Interface**

**   ****SQLCALLBACK****(SQLFile,FCB.SQLCallBackInterface)          !Register Interface**

**    CREATE(Logfile)                                        !Create log file**

**    OPEN(Logfile)                                          !Open log file**

**    OPEN(People)                                           !Open data file**

**    SET(PEO:KeyId, PEO:KeyID)                              !Set and **

**    LOOP                                                   !loop thru**

**      NEXT(People)                                         !data until**

**      IF ERRORCODE() THEN BREAK END                        !end of file**

**    END**

**    CLOSE(People)                                          !Close data file**

**    SQLFile{PROP:SQL} = 'CREATE TABLE sptesttable (c INT)' !Create SQL table**

**    OPEN(SQLFile)                                          !Open SQL table**

**    SQLFile.Id=5**

**    ADD(SQLFile)                                           !Update SQL table**

**    SQLFile.Id=7**

**    ADD(SQLFile)                                           !Update SQL table**

**    SQLFile.Id=8**

**    ADD(SQLFile)                                           !Update SQL table**

**    CLOSE(SQLFile)                                         !Close SQL table**

**    CALLBACK(People,FCB.FileCallBackInterface, TRUE)       !Unregister Interface**

**   ****SQLCALLBACK****(SQLFile,FCB.SQLCallBackInterface, TRUE)    !Unregister Interface**

**!This method is called prior to each operation of the data file. The log file is updated**

**!with the file operation that is being executed.**

**FCB.FileCallBackInterface.FunctionCalled |**

**    PROCEDURE(SIGNED opCode, *Params Parameters, *CSTRING ErrCode, *CSTRING ErrMsg)**

**p LIKE(Params)**

**  CODE**

**    p = Parameters**

**    CASE opCode**

**    OF DriverOp:ADD**

**      logFile.Operation = 'ADD(f)'**

**    OF DriverOp:APPEND**

**      logFile.Operation = 'APPEND(f)'**

**    OF DriverOp:CLOSE**

**      logFile.Operation = 'CLOSE(f)'**

**    OF DriverOp:COPY**

**      logFile.Operation = 'COPY(f,'''&CLIP(Parameters.Text)&''')'**

**    OF DriverOp:CREATE**

**      logFile.Operation = 'CREATE(f)'**

**    OF DriverOp:DELETE**

**      logFile.Operation = 'DELETE(f)'**

**    OF DriverOp:NEXT**

**      logFile.Operation = 'NEXT(f)'**

**    OF DriverOp:OPEN**

**      logFile.Operation = 'OPEN(f,'&Parameters.openMode&')'**

**    OF DriverOp:PUT**

**      logFile.Operation = 'PUT(f)'**

**    OF DriverOp:SETkeykey**

**      logFile.Operation = 'SET(k,k)'**

**    END**

**    ADD(logFile)**

**    RETURN TRUE**

**!This method is called after each operation to the data file. This simply returns a TRUE !according to the rules of the FileCallBackInterface.**

**FCB.FileCallBackInterface.FunctionDone |**

**    PROCEDURE(SIGNED opCode, Params Parameters, *CSTRING ErrCode, *CSTRING ErrMsg)**

**  CODE**

**    RETURN TRUE**

**!This method is called just before the SQL statement is passed to the SQL server for !execution**

**FCB.SQLCallBackInterface.ExecutingCode |**

**    PROCEDURE(CONST *CSTRING inStr, *BYTE Err, *CSTRING ErrCode, *CSTRING ErrMsg)**

**  CODE**

**    Err = FALSE**

**    RETURN inStrPUT_re_write_record**