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Fix ALTER DOMAIN NOT NULL syntax

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This addresses a few problems with commit e5da0fe3c2 ("Catalog domain
not-null constraints").

In CREATE DOMAIN, a NOT NULL constraint looks like

    CREATE DOMAIN d1 AS int [ CONSTRAINT conname ] NOT NULL

(Before e5da0fe3c2, the constraint name was accepted but ignored.)

But in ALTER DOMAIN, a NOT NULL constraint looks like

    ALTER DOMAIN d1 ADD [ CONSTRAINT conname ] NOT NULL VALUE

where VALUE is where for a table constraint the column name would be.
(This works as of e5da0fe3c2.  Before e5da0fe3c2, this syntax
resulted in an internal error.)

But for domains, this latter syntax is confusing and needlessly
inconsistent between CREATE and ALTER.  So this changes it to just

    ALTER DOMAIN d1 ADD [ CONSTRAINT conname ] NOT NULL

(None of these syntaxes are per SQL standard; we are just living with
the bits of inconsistency that have built up over time.)

In passing, this also changes the psql \dD output to not show not-null
constraints in the column "Check", since it's already shown in the
column "Nullable".  This has also been off since e5da0fe3c2.

Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/9ec24d7b-633d-463a-84c6-7acff769c9e8%40eisentraut.org
This commit is contained in:
Peter Eisentraut
2024-04-15 08:20:34 +02:00
parent d21d61b96f
commit 9895b35cb8
6 changed files with 99 additions and 16 deletions
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60
src/backend/parser/gram.y
View File

@@ -524,7 +524,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <vsetstmt> generic_set set_rest set_rest_more generic_reset reset_rest
SetResetClause FunctionSetResetClause
%type <node> TableElement TypedTableElement ConstraintElem TableFuncElement
%type <node> TableElement TypedTableElement ConstraintElem DomainConstraintElem TableFuncElement
%type <node> columnDef columnOptions optionalPeriodName
%type <defelt> def_elem reloption_elem old_aggr_elem operator_def_elem
%type <node> def_arg columnElem where_clause where_or_current_clause
@@ -596,7 +596,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <keyword> col_name_keyword reserved_keyword
%type <keyword> bare_label_keyword
%type <node> TableConstraint TableLikeClause
%type <node> DomainConstraint TableConstraint TableLikeClause
%type <ival> TableLikeOptionList TableLikeOption
%type <str> column_compression opt_column_compression column_storage opt_column_storage
%type <list> ColQualList
@@ -4334,6 +4334,60 @@ ConstraintElem:
}
;
/*
* DomainConstraint is separate from TableConstraint because the syntax for
* NOT NULL constraints is different. For table constraints, we need to
* accept a column name, but for domain constraints, we don't. (We could
* accept something like NOT NULL VALUE, but that seems weird.) CREATE DOMAIN
* (which uses ColQualList) has for a long time accepted NOT NULL without a
* column name, so it makes sense that ALTER DOMAIN (which uses
* DomainConstraint) does as well. None of these syntaxes are per SQL
* standard; we are just living with the bits of inconsistency that have built
* up over time.
*/
DomainConstraint:
CONSTRAINT name DomainConstraintElem
{
Constraint *n = castNode(Constraint, $3);
n->conname = $2;
n->location = @1;
$$ = (Node *) n;
}
| DomainConstraintElem { $$ = $1; }
;
DomainConstraintElem:
CHECK '(' a_expr ')' ConstraintAttributeSpec
{
Constraint *n = makeNode(Constraint);
n->contype = CONSTR_CHECK;
n->location = @1;
n->raw_expr = $3;
n->cooked_expr = NULL;
processCASbits($5, @5, "CHECK",
NULL, NULL, &n->skip_validation,
&n->is_no_inherit, yyscanner);
n->initially_valid = !n->skip_validation;
$$ = (Node *) n;
}
| NOT NULL_P ConstraintAttributeSpec
{
Constraint *n = makeNode(Constraint);
n->contype = CONSTR_NOTNULL;
n->location = @1;
n->keys = list_make1(makeString("value"));
/* no NOT VALID support yet */
processCASbits($3, @3, "NOT NULL",
NULL, NULL, NULL,
&n->is_no_inherit, yyscanner);
n->initially_valid = true;
$$ = (Node *) n;
}
;
opt_no_inherit: NO INHERIT { $$ = true; }
| /* EMPTY */ { $$ = false; }
;
@@ -11586,7 +11640,7 @@ AlterDomainStmt:
$$ = (Node *) n;
}
/* ALTER DOMAIN <domain> ADD CONSTRAINT ... */
| ALTER DOMAIN_P any_name ADD_P TableConstraint
| ALTER DOMAIN_P any_name ADD_P DomainConstraint
{
AlterDomainStmt *n = makeNode(AlterDomainStmt);