Building UDFs

Design, build, and test UDFs.

• Design Basics of User-Defined Functions
  There are some basic considerations to keep in mind while developing UDFs.
• Setting the Dynamic Library Interface
  Specify the interface style to be used in the dynamically linkable library.
• Upgrading to the v4 API
  Sybase recommends that you upgrade to the v4 API included with 15.4.
• Library Version (extfn_get_library_version)
  Use the extfn_get_library_version method to extract the library version from the current multiplex node. The server considers partitioning a query across multiplex nodes only if the installed library is compatible with the other nodes.
• Library Version Compatibility (extfn_check_version_compatibility)
  Use the extfn_check_version_compatibility method to define compatibility criteria for library versions across nodes in a multiplex.
• License Information (extfn_get_license_info)
  If you are a Sybase design partner, implement the extfn_get_license_info library-level function to enable the server to obtain licensing information from a v4 UDF.
• Compile and Link Source Code to Build Dynamically Linkable Libraries
  Use compile and link switches when building dynamically linkable libraries for any user-defined function.
• Testing User-Defined Functions
  After UDF external code has been coded, compiled and linked, and the corresponding SQL functions and stored procedures have been defined, the UDFs are ready to be tested.
• Modifying the UDF at Runtime
  Many Sybase IQ installations are in mission-critical environments, where customers require an extremely high level of availability. System Administrators must be able to install and upgrade UDFs with little or no impact to the Sybase IQ server.
• Granting and Revoking Permissions
  A user-defined function is owned by the user who created it, by default, although the creator can specify another owner at creation time.
• Dropping User-Defined Functions
  Once you create a user-defined function, it remains in the database until it is explicitly removed. Only the owner of the function or procedure, or a user with DBA authority, can drop a function or procedure from the database.