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

Schema/Tuple

heading(schema)

type
attr

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

Find the names of the variables in the current schema

heading(schema){attr}

attr

$P
$S
$SP
$constraint
error