Local SQL Functions
The Rules Engine is able to resolve many SQL functions locally. This way the number of trips to the database is minimized.
You can use all SQL functions supported by your RDBMS (please consult the database vendor's SQL syntax documentation) but if the Rules Engine does not support the function, each time it is called a trip to the database is necessary.
You can improve performance by avoiding RDBMS-specific functions where possible. You also benefit from this strategy when migrating to another RDBMS.
Find out which SQL functions are supported locally by the Rules Engine by referring to the listings in the Available SQL Functions section of the Definer help.
There are a number of borderline cases. For instance, LTRIM and RTRIM are possible against both Oracle and Sybase and are also ODBC functions, but because these platforms handle these functions differently they are not resolved locally.
SUBSTR and INSTR are handled locally by USoft, but because these functions are handled differently on Sybase than on for example Oracle, the Rules Engine may adjust the number of parameters by truncating the function call as it was submitted, or by adding dummy parameter values.
For these borderline cases, refer to the listings in the Available SQL Functions section of the Definer help.