Jim_Callahan
Member
Pass through queries can be used to define linked data bases, but not all linked data bases require pass through queries. An MS Access database linking to another MS Access database is one example that would not require a pass-through query.
Pass through queries are useful when you want to either:
1. Take advantage of non-standard (or non-SQL) query syntax on the linked to database.
Examples:
a. Using an IBM Db2 specific SQL syntax
b Linking to an MS Anaysis Services (multi-dimensional OLAP cube with non-SQL syntax)
or 2. take advantage of summarization on the linked to data base.
Larry Jones wrote:
> The definition of a Pass-Through query (For Access) is:
> "An SQL-specific query you use to send commands
> directly to an ODBC database server (such as Microsoft
> SQL Server). By using pass-through queries, you work
> directly with the tables on the server instead of having the
> Microsoft Jet database engine process the data."
> Given that definition, do you really need to use a Pass-
> Through query as opposed to regular SQL queries?
> 1. I doubt that the ODA ODBC driver supports pass-through
YES, EXCELLENT POINT! Support of pass-through queries by ODA would raise data security issues (is ODA still "read only" since one might be able to pass-through a data altering query) and by definition ODA would not be able to intercept SQL calls and convert dates and apply decimal places based on the data dictionary. In other words supporting pass through queries would defeat the 3 main purposes of ODA!
> 2. If you really need pass-through capability, then you want
> to use the ODBC/OLEDB driver for your actual database -
> not ODA
Given the above, yes, I would have to agree.
One option would be to have MS SQL Server do the query and have present a safe, read-only view to the MS Access client.
HTH,
Jim Callahan
Pass through queries are useful when you want to either:
1. Take advantage of non-standard (or non-SQL) query syntax on the linked to database.
Examples:
a. Using an IBM Db2 specific SQL syntax
b Linking to an MS Anaysis Services (multi-dimensional OLAP cube with non-SQL syntax)
or 2. take advantage of summarization on the linked to data base.
Larry Jones wrote:
> The definition of a Pass-Through query (For Access) is:
> "An SQL-specific query you use to send commands
> directly to an ODBC database server (such as Microsoft
> SQL Server). By using pass-through queries, you work
> directly with the tables on the server instead of having the
> Microsoft Jet database engine process the data."
> Given that definition, do you really need to use a Pass-
> Through query as opposed to regular SQL queries?
> 1. I doubt that the ODA ODBC driver supports pass-through
YES, EXCELLENT POINT! Support of pass-through queries by ODA would raise data security issues (is ODA still "read only" since one might be able to pass-through a data altering query) and by definition ODA would not be able to intercept SQL calls and convert dates and apply decimal places based on the data dictionary. In other words supporting pass through queries would defeat the 3 main purposes of ODA!
> 2. If you really need pass-through capability, then you want
> to use the ODBC/OLEDB driver for your actual database -
> not ODA
Given the above, yes, I would have to agree.
One option would be to have MS SQL Server do the query and have present a safe, read-only view to the MS Access client.
HTH,
Jim Callahan