From fc22b6623b6b3bab3cb057ccd282c2bfad1a0b30 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Sat, 30 Mar 2019 08:13:09 +0100 Subject: Generated columns This is an SQL-standard feature that allows creating columns that are computed from expressions rather than assigned, similar to a view or materialized view but on a column basis. This implements one kind of generated column: stored (computed on write). Another kind, virtual (computed on read), is planned for the future, and some room is left for it. Reviewed-by: Michael Paquier Reviewed-by: Pavel Stehule Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com --- src/backend/parser/parse_expr.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'src/backend/parser/parse_expr.c') diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 3e648dc8ef9..20d923203f4 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -570,6 +570,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) case EXPR_KIND_PARTITION_EXPRESSION: case EXPR_KIND_CALL_ARGUMENT: case EXPR_KIND_COPY_WHERE: + case EXPR_KIND_GENERATED_COLUMN: /* okay */ break; @@ -1927,6 +1928,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_COPY_WHERE: err = _("cannot use subquery in COPY FROM WHERE condition"); break; + case EXPR_KIND_GENERATED_COLUMN: + err = _("cannot use subquery in column generation expression"); + break; /* * There is intentionally no default: case here, so that the @@ -3557,6 +3561,8 @@ ParseExprKindName(ParseExprKind exprKind) return "CALL"; case EXPR_KIND_COPY_WHERE: return "WHERE"; + case EXPR_KIND_GENERATED_COLUMN: + return "GENERATED AS"; /* * There is intentionally no default: case here, so that the -- cgit v1.2.3