SQLGetData - cSQLStatement

Get data of a column in chunks (variable length data)

Type: Function
Return Data Type: String

Parameters

Parameter	Type	Description
iCol	Integer	Column to get data from
iLen	Integer	Length of data to get

Syntax

Function SQLGetData Integer iCol Integer iLen Returns String

Call Example

Get SQLGetData iCol iLen to StringVariable

Description

In DataFlex 20.0 and higher, SQLGetData cannot be used to get binary data, as binary data can no longer be stored in string variables. SQLGetData is a legacy method and cannot handle characters split across 2 chunks of data. Use SQLGetDataToUChar instead to correctly retrieve such data.

Get the value of a column. SQLGetData is intended to get column data in chunks. If a statement selects a large object column, BLOB, CLOB, it is impossible to get the data of that column in one call. Normally the exact size of the column is not known upfront and it can grow to very big proportions (4 GB in some backends). In such cases, you can use SQLGetData to get the column value piece by piece.

The function will fill the global integer status variable SQLResult when the last chunk of data is retrieved. It will return the chunk of data that was retrieved.

If the column is less than 16 KB, use SQLColumnValue.

Sample

This code sample shows how to use SQLGetData to get a column's data in chunks of 1 KB.

Handle hoSQLMngr
Handle hdbc hstmt
Integer iFetchResult
String sChunk

Object oSQLHandler Is A cSQLHandleManager
    Move Self to hoSQLMngr
End_Object

Get SQLFileConnect of hoSQLMngr Customer.File_number to hdbc
Get SQLOpen of hdbc to hstmt
Send SQLExecDirect of hstmt "SELECT photograph from employee"
Repeat
    Get SQLFetch of hstmt to iFetchResult
    If (iFetchResult <> 0) Begin
        Repeat
            Get SQLGetData of hstmt 1 1024 to sChunk
            Send HandlePictureChunk to hoPicturehandler sChunk
        Until (SQLResult <> SQLSuccess)
    End
Until (iFetchResult = 0)

Send SQLClose of hstmt
Send SQLDisconnect of hdbc

If you are executing a SELECT statement that returns multiple columns, the text or varchar columns must be last in the SELECT statement or you may get an "invalid desriptor index" error.

Return Value

Returns data from a column.