ODBC 3.0

Version 3.0 is a major update to ODBC--more major than previous versionshave been. To align it with the new standard, Microsoft added about 20 functioncalls, additional data types, and scalar functions.

ODBC 3.0 includes binding, fetching, and bookmark enhancements. It providesvariable-length bookmarks and can update and delete using bookmarks. It supportsfetches based on search conditions, row-wise parameter binding, and quickrebinding using offsets from bound-
variable addresses.

Programmers writing for ODBC 2.0 use connection and statement options togovern behavior such as whether a driver should use native cursors or the ODBCCursor Library. ODBC 3.0 supersedes these options with attributes and addsapplication-level environment attributes. It also adds diagnostic datastructures to make error handling more flexible.

Previously, an application typically used a loop to call SQLError for errorcodes and messages. SQLError has a fixed number of arguments and returns, butthe new diagnostics use extensible data structures so you can provide additionalerror information.

ODBC 3.0 adds descriptors comparable to those in SQL-92 and similar to theinformation stored in the SQL Descriptor Area (SQLDA) of embedded SQL programs.Descriptors are data structures that store information about rowsor parameters. Applications can use a number of descriptors, so version 3.0 useshandles to keep track of them. It adds a new generic handle-allocation function,SQLAllocHandle, that lets you define it as an environment, connection,statement, or descriptor handle.

Version 3.0 changes the date/time data type and adds large binary andcharacter objects, intervals, and Unicode data types. It also supports ANSI andUnicode versions of all functions. ODBC 3.0 adds SQL3-style locators to handlelarge objects and several new locator functions (e.g., SQLGetPosition andSQLGetSubString) to work with substrings within large character objects.Finally, version 3.0 adds an uninstaller and views to expose schema information.