Defining PostgreSQL Functions

The following properties are applicable to a PostgreSQL Function object.

Tab	Section	Property	Description	Additional Information
		Name	Specifies the name of the function
		Use Replace Syntax	Specifies whether the REPLACE syntax is used	Selecting this option replaces the syntax with the new DDL that is generated during Forward Engineering
		Schema	Specifies the schema for the function
		Generate	Specifies whether a SQL statement for the collation is generated during forward engineering
General	Function Options	Language	Specifies the name of the language in which the function is implemented	Internal, c, Sql, User Defined: Specifies procedural languages of the function
		Transform	Lists which transforms a call to the function should apply. Transforms convert between SQL types and language-specific data types
		Is Window	Indicates that the function is a window function rather than a plain function, which is currently only useful for functions written in C
		Volatility	Informs the query optimizer about the behavior of the function	Immutable: Indicates that the function cannot modify the database and always returns the same result when given the same argument values. That is, it does not do database lookups or otherwise use information not directly present in its argument list. Stable: Indicates that the function cannot modify the database, and that within a single table scan it will consistently return the same result for the same argument values but that its result could change across SQL statements Volatile: Indicates that the function value can change within a single table scan, preventing any optimizations. Relatively few database functions are volatile in this sense; examples include random(), currval(), and timeofday().
		Leak Proof	Indicates that the function has no side effects. It reveals no information about its arguments other than by its return value	LEAKPROOF: Indicates that the function has no side effects. It reveals no information about its arguments other than by its return value. NOT LEAKPROOF: A function that might throw an error based on the values received as arguments (such as one that throws an error due to overflow or division by zero) is not leak-proof and could reveal significant information about unseen rows if applied before the security view's row filters.
		Null_Input_Type		Called on null input: Indicates that the function is called correctly even when some parameters are null. Function authors must check for null values and respond appropriately. Returns null on null input or Strict: Specifies that the method returns null when any parameters are null. When this option is set, the function is not performed with null parameters, and a null result is presumed.
		Security_Type	Specifies the privilege that is to be used to execute the function	Definer: Specifies that the function is to be executed with the privileges of the user that owns it. Invoker: indicates that the function is to be executed with the privileges of the user that calls it.
		External	This is optional for SQL conformance, as it applies to all functions, not just external ones.
		Parallel	Specifies the mode of execution of the function	Unsafe: Indicates that the function can not be executed in parallel mode. The presence of such a function in an SQL statement forces a serial execution plan. Safe: Indicates that the function can run in parallel mode without restriction. Restricted: Indicates that the function can be executed in parallel mode, but the execution is restricted to parallel group leader.
		Execution Cost	Specifies a positive number giving the estimated execution cost for the function, in units of cpu_operator_cost. If the function returns a set, this is the cost per returned row. If the cost is not specified, 1 unit is assumed for C-language and internal functions, and 100 units for functions in all other languages.
		Returns Set	Indicates that the function will return a set of items rather than a single item.
		Result Row	Specifies a positive number indicating the estimated rows the planner should expect the function to return when it returns a set. The default is 1000 rows.
		Support Function	Specifies the name (optionally schema-qualified) of a planner support function to use for this function	Ensure that you have a superuser role to use this function.
		As Function Definition	Defines the function's meaning and can be an internal function name, object file location, SQL command, or procedural text. Dollar quoting is useful for syntax.
		Object File	Specifies the name of the file containing the dynamically loadable object for C language functions
		Link Symbol	Specifies the function's link symbol, which is the name of the function in the C language source code. If you omit the link symbol, it assumes to be the same as the name of the SQL function being defined
		SQL Body	Specifies the body of a LANGUAGE SQL function. This can either be a single statement
	Returns Options	Function Type	Specifies the type of the function	Scalar: Specifies that it uses the default return type and emits all parameters. Table: Specifies that the return definition of the function is a table, using this option will only emit IN parameters in the arguments Trigger: Specifies that the defined function is a trigger function Type: Specifies to accept user-defined function type
		Return Data Type	Specifies the return data type of the function
		Return Table Definition	Specify the referenced table
		Return Table Column Specification	Specifies the schema of table columns that the function returns
Parameters		Parameters	Specifies the name of the parameter
		Physical Data Type	Specifies the return data type of the parameter
		Mode	Specifies the type of the parameter
		Default Value	Specifies an expression that can be used as default value if the parameter is not specified. The expression has to be coercible to the argument type of the parameter. Only input (including IN OUT) parameters can have a default value.
Variables		Variables	Specifies the name of the variable
Variables		Variable value	Specifies an expression to use as the variable value

Work with the other tabs in the editor to access additional design features, for example:
- Define the code type in the Code tab.
- View expanded code in the Expanded tab.
- Define function permissions using the Permission tab.
- Specify the order of DDL generation in the Object Creation Order tab.
(Optional) Click the Comment tab and enter any comments you want to associate with the object.
(Optional) Click the Where Used tab to view where the object is used within the model.
(Optional) Click the UDP tab to work with user-defined properties for the object.
(Optional) Click the Notes tab to view and edit user notes.
(Optional) Click the Extended Notes tab to view or edit user notes.
Click Close.
The function is defined and the PostgreSQL Function Editor closes.

For more information, refer to PostgreSQL documentation.