RWDBDataCallback::getLength()

SourcePro : DB Access Module for Microsoft SQL Server User’s Guide : Technical Information : Open SQL and Microsoft SQL Server ODBC : RWDBDataCallback and Open SQL : RWDBDataCallback::getLength()

When inserting data using data callbacks, some databases need to be provided the total length of the inserted value, which requires overriding the RWDBDataCallback::getLength() method.

When using the SQL Server Native Client or ODBC Driver for SQL Server

The Microsoft SQL Server Native Client and ODBC Driver for SQL Server do not need the total length of the value, although there are potential performance benefits to using it. Therefore, overriding the RWDBDataCallback::getLength() method may be desirable but is not required.

When using the Microsoft SQL Server MDAC Client

The MDAC Client requires the total length of the insert value to insert data successfully. Therefore, the method RWDBDataCallback::getLength() must be overridden when inserting data.