Micro Focus Enterprise Developer 3.0 for Eclipse > Programming > Mainframe Programming > HCO for SQL Server (HCOSS) > Migrating Applications > DB2 to SQL Server Conversion > Application Progression from DB2 to SQL Server

Application Progression from DB2 to SQL Server

Restriction: This topic applies to Windows environments only.

As your application progresses from being a mainframe DB2 application to being a SQL Server application with no residual dependencies on mainframe characteristics, the combination of DIALECT settings and statement prefixes required when compiling and binding change, depending on the stage of the progression, to ensure optimal DB2 to SQL Server conversion results. The following scenario suggests each stage of application progression along with the combination of DIALECT and statement prefix settings recommended for each stage:

Stage 1 - All statements are DB2 compatible

Recommended settings:

DIALECT Setting	Statement Prefix
MAINFRAME	None

The preprocessor attempts to process all statements as DB2 statements and issues a DB2 compatibility warning on each statement that HCOSS does not recognize as a valid DB2 statement, but that is otherwise compatible with SQL Server. Only statements that compile without DB2 compatibility warnings are qualified by the QUALIFIER compiler directive or BIND parameter.

Stage 2 - Some statements are SQL Server specific; most are mainframe compatible

Recommended settings:

DIALECT Setting	Statement Prefix
MAINFRAME	[NODIALECT] on statements you want to flag as SQL Server compatible

The [NODIALECT] prefix suppresses the DB2 compatibility warning on statements that are only compatible with SQL Server. Since. due to the DIALECT=MAINFRAME setting, these statements are not qualified by the QUALIFIER compiler directive option or the BIND QUALIFIER parameter, ensure that the statements are either explicitly qualified in the source code or that the default schema for the connection points SQL Server to the correct schema.

Stage 3 - Most statements are SQL Server compatible

Recommended settings:

DIALECT Setting	Statement Prefix
MIXED	[MAINFRAME] on statements that fail with SQL(CHECK) and that are not ready for conversion to SQL Server

You may remove [NODIALECT] prefixes at this stage if you want, but it is not required.

Stage 4 - First class SQL Server Application

Recommended settings:

DIALECT Setting	Statement Prefix
NONE	None

Remove all [MAINFRAME] and [NODIALECT] statement prefixes specified for previous stages. These prefixes cause compilation errors when DIALECT is set to NONE. However, you can specify the [NOPLAN] prefix on statements of your choice.