random_variable_type.c File Reference

PostgreSQL I/O and constructor functions for the random_variable type. More...

#include "postgres.h"
#include "fmgr.h"
#include "utils/uuid.h"
#include "utils/fmgrprotos.h"

Include dependency graph for random_variable_type.c:

Go to the source code of this file.

Classes
struct	random_variable
	Binary internal layout of random_variable. More...

Functions
Datum	random_variable_in (PG_FUNCTION_ARGS)
	Parse a random_variable from its text representation.
Datum	random_variable_out (PG_FUNCTION_ARGS)
	Render a random_variable as a hyphenated UUID string.
Datum	random_variable_make (PG_FUNCTION_ARGS)
	Build a random_variable from a UUID.

Detailed Description

PostgreSQL I/O and constructor functions for the random_variable type.

random_variable is a thin wrapper around a provenance gate UUID, used in user-facing SQL for continuous probabilistic c-tables.

On-disk and on-wire text format: the canonical xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx UUID form (identical to PostgreSQL's uuid). A binary-coercible random_variable -> uuid cast (declared WITHOUT FUNCTION since the two types share their byte layout) keeps SQL ergonomics: an rv-typed column flows directly into any function that accepts a uuid at zero runtime cost.

Definition in file random_variable_type.c.

Function Documentation

random_variable_in()

Datum random_variable_in

(

PG_FUNCTION_ARGS

)

Parse a random_variable from its text representation.

Expected format: the standard hyphenated UUID xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, delegated to uuid_in. Raises ERROR on malformed input.

Definition at line 42 of file random_variable_type.c.

random_variable_make()

Datum random_variable_make

(

PG_FUNCTION_ARGS

)

Build a random_variable from a UUID.

Internal constructor used by the provsql.normal / provsql.uniform / provsql.exponential / provsql.as_random SQL constructors after they have created the backing gate. Equivalent in effect to the binary-coercible uuid -> random_variable cast (both reinterpret the same 16 bytes), but kept as a named function so the constructors read uniformly with the rest of the SQL surface.

Definition at line 75 of file random_variable_type.c.

random_variable_out()

Datum random_variable_out

(

PG_FUNCTION_ARGS

)

Render a random_variable as a hyphenated UUID string.

Definition at line 56 of file random_variable_type.c.