Reading from a LONG RAW column

4D v16

You can use 4D for OCI to read the contents of a LONG RAW column in an Oracle database under the following conditions:

the receiving variable must be of the BLOB type
the datatype must be SQLT_LBI
the mode must be OCI_DYNAMIC_FETCH (and not OCI_DEFAULT)

例題

  //Method: Read_long_raw

  //reads data from a long raw column

  //and creates the picture file (jpg) in the database folder

 

 C_LONGINT(envhp;errhp;svchp;vDefine;stmthp;stmtSelecthp)

 C_LONGINT(RealLength)

 C_BLOB(TheBlob)

 

  //--------------------------------------------

  //CONDITION 1: Blob

 SET BLOB SIZE(TheBlob;0)

  //--------------------------------------------

 

 C_POINTER(vp_Null1;vp_Null3)

 ReadLength:=0

 

 C_TEXT($UserName;$Password;$ServiceName;$SQL_statement)

 

 $UserName:="xxx"

 $Password:="xxx"

 $ServiceName:="xxx"

 

 Status:=OCIEnvCreate(envhp;OCI_OBJECT)

 Status:=OCIHandleAlloc(envhp;errhp;OCI_HTYPE_ERROR)

 Status:=OCILogon(envhp;errhp;svchp;$UserName;$Password;$ServiceName)

 Status:=OCIHandleAlloc(envhp;stmthp;OCI_HTYPE_STMT)

 

 $SQL_statement:="SELECT lgraw FROM test_LGRAW WHERE key = 20"

 Status:=OCIHandleAlloc(envhp;stmtSelecthp;OCI_HTYPE_STMT)

 If(Status=OCI_SUCCESS)

    Status:=OCIStmtPrepare(stmtSelecthp;errhp;$SQL_statement;OCI_DEFAULT)

 

  //--------------------------------------------

  //CONDITION 2: SQLT_LBI for LONG RAW

  //CONDITION 3: OCI_DYNAMIC_FETCH instead of OCI_DEFAULT

 

    Status:=OCIDefineByPos(stmtSelecthp;vDefine;errhp;1;->TheBlob;SQLT_LBI;vp_Null1;

    ->ReadLength;vp_Null3;OCI_DYNAMIC_FETCH)

  //--------------------------------------------

 

    $status:=OCIErrorGet(errhp;1;$errornum;$errorexplain)

    If($errornum#0)

       ALERT(String($errornum)+Char(13)+$errorexplain)

    End if

    Repeat

       Status:=OCIStmtExecute(svchp;stmtSelecthp;errhp;1;0;0;0;OCI_DEFAULT)

    Until(Status#OCI_STILL_EXECUTING)

    Status:=OCIHandleFree(stmtSelecthp)

 End if

 

  //remove the first 8 characters if the picture was inserted with 4D for Oracle

 DELETE FROM BLOB(TheBlob;0;8)

 

 If(ReadLength>0)

    $DocRef:=Create document("longraw_image.jpg")

    If(OK=1)

       CLOSE DOCUMENT($DocRef)

       BLOB TO DOCUMENT(Document;TheBlob)

    End if

 Else

    ALERT("Blob size: zero!")

 End if

 

 Status:=OCIHandleFree(stmthp)

 Status:=OCILogoff(svchp;errhp)

 Status:=OCIHandleFree(errhp)

 Status:=OCIHandleFree(envhp)

 

 SET BLOB SIZE(TheBlob;0) //empty Blob

 

  //End of method