[DERBY-475] Add a system function mechanism and table of functions, including a set of initial functions.

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 10.2.1.6
• Component/s: SQL
• Assignee: Daniel John Debrunner
• Reporter: Daniel John Debrunner
• Created: 28/Jul/05 07:22
• Updated: 10/Sep/07 10:08
• Resolved: 03/Feb/06 04:55

Description

Add a mechanism for system functions to be easily added. Resolution of functions will check SYSFUN.<name> for a function call in SQL when the function is not qualified by a schema. If the current schema does not have a function matching the name, then an additional resolution is made using SYSFUN.<name>.

Add a table driven mechanism for simple single argument functions (could be expanded in the future).

Add these functions

/*

• • SYSFUN functions
    *[0] = FUNCTION name
    *[1] = RETURNS type
    *[2] = Java class
    *[3] = method name
    *[4] = parameter type (single parameter)
    *
    */
    private static final String[][] SYSFUN_FUNCTIONS = { {"ACOS", "DOUBLE", "java.lang.Math", "acos", "DOUBLE"}

    ,

    {"ASIN", "DOUBLE", "java.lang.Math", "asin", "DOUBLE"}

    ,

    {"ATAN", "DOUBLE", "java.lang.Math", "atan", "DOUBLE"}

    ,

    {"COS", "DOUBLE", "java.lang.Math", "cos", "DOUBLE"}

    ,

    {"SIN", "DOUBLE", "java.lang.Math", "sin", "DOUBLE"}

    ,

    {"TAN", "DOUBLE", "java.lang.Math", "tan", "DOUBLE"}

    ,

    {"DEGREES", "DOUBLE", "java.lang.Math", "toDegrees", "DOUBLE"}

    ,

    {"RADIANS", "DOUBLE", "java.lang.Math", "toRadians", "DOUBLE"}

    ,

    {"LN", "DOUBLE", "java.lang.Math", "log", "DOUBLE"}

    ,

    {"EXP", "DOUBLE", "java.lang.Math", "exp", "DOUBLE"}

    ,

    {"CEIL", "DOUBLE", "java.lang.Math", "ceil", "DOUBLE"}

    ,

    {"CEILING", "DOUBLE", "java.lang.Math", "ceil", "DOUBLE"}

    ,

    {"FLOOR", "DOUBLE", "java.lang.Math", "floor", "DOUBLE"}

    ,

};

Issue Links

• is depended upon by: DERBY-3063 Extend the system function mechanism to support functions with multiple arguments
• relates to: DERBY-591 Several builtin functions are incorrectly exposed through the JDBC escaped function syntax {fn <function_call>}
• relates to: DERBY-1548 Document builtin functions - ACOS, ASIN, ATAN, COS, SIN, TAN, PI, DEGREES, RADIANS, EXP, LN, LOG, LOG10, CEIL, CEILING, FLOOR