Builtin

heading

heading(a)

Returns the heading {attr, type} for a as a relation.

Examples

Relation

heading($S)

attr type

SNO str
SNAME str
STATUS int
CITY str

attr	type
SNO	str
SNAME	str
STATUS	int
CITY	str

Schema/Tuple

heading(schema)

attr type

$constraint {name:str,rule:str}
$S {SNO:str,SNAME:str,STATUS:int,CITY:str}
$P {PNO:str,PNAME:str,COLOR:str,WEIGHT:int,CITY:str}
$SP {SNO:str,PNO:str,QTY:int}
error {name:str,message:str}

attr	type
$constraint	{name:str,rule:str}
$S	{SNO:str,SNAME:str,STATUS:int,CITY:str}
$P	{PNO:str,PNAME:str,COLOR:str,WEIGHT:int,CITY:str}
$SP	{SNO:str,PNO:str,QTY:int}
error	{name:str,message:str}

Find the names of the variables in the current schema

heading(schema){attr}

attr

$P
$S
$SP
$constraint
error