Home > Mobile >  ODBC and data binding by [Table].[column]
ODBC and data binding by [Table].[column]

Time:08-28

I'm rewriting an older-than-dirt MFC application, ripping out the old MFC-based DB code and re-working queries to make it run faster. This code works with a MS Access 2003 .mdb file. The old code used the convenience functions like RFX_Bool, RFX_Long, RFX_Int to read from the records. These are nice, and I am reading about binding in ODBC using SQLBindCol to set the bindings ahead of time to avoid that extra processing time for each row. This is great, but I see SQLBindCol only takes the column number, not the name. What if I want to bind using the column name like with the RFX_* functions? SQLDescribeCol gives the column names, but it doesn't have the "full" name, i.e. [Table/Alias].[Column]. Some of my queries involve JOIN'ing the same table multiple times with aliases, so I can't bind the column by the column name alone. If I plug my query into Access, the Datasheet view shows the alias in the column name. I'm currently using my connection string with Driver={Microsoft Access Driver (*.mdb, *.accdb)}, if it matters.

tl;dr How do I do MFC's RFX_*(fieldExchange, L"[Table].[Column]", &variable) in the modern ODBC API?

CodePudding user response:

OK, I think I understand what the RFX functions are doing now, and I think I know what I need to do.

The MFC ODBC classes construct your query programmatically, so after starting with SELECT, UPDATE, etc, every call to RFX_* simply appends the field name to the query, then ties a reference to your variable to the column index, which it increments after every call. So I just need to append my fields to my queries with a helper function the same way MFC does, in order to bind my pointers in the same way MFC does.

Hopefully this is helpful to somebody.

  • Related