A database function name (dbfunction_name) identifies a database function. Database functions are specialized database procedures. They are subroutines that contain any number of input parameters but only one output parameter, which supplies the result of the function.
<dbfunction_name> ::= [<schema_name>.]<identifier>
The identifier must not exceed 32 characters in length.
You can define user-specific functions to transfer application logic to the server of the database system, which you can use similarly to predefined functions. When naming your functions, make sure you do not use the names of predefined functions (Functions: Overview).
The database system provides a language (special SQL syntax that has been extended to include variables, control structures, and troubleshooting measures) that allows an SQL access layer to be formulated on the server side. This special SQL syntax can be used to define database functions, which can be executed by a function call of an SQL statement (database function call).
Database Function Call (dbfunction_call)