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| author | Peter Eisentraut <peter@eisentraut.org> | 2019-03-30 08:13:09 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2019-03-30 08:15:57 +0100 |
| commit | fc22b6623b6b3bab3cb057ccd282c2bfad1a0b30 (patch) | |
| tree | cda5092955ece5d547d5517ed56a3d480f199d25 /src/backend/parser/parse_expr.c | |
| parent | 6b8b5364ddd0e4d882562615c6b6c28638ade9f2 (diff) | |
| download | postgresql-fc22b6623b6b3bab3cb057ccd282c2bfad1a0b30.tar.gz postgresql-fc22b6623b6b3bab3cb057ccd282c2bfad1a0b30.zip | |
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 <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 6 |
1 files changed, 6 insertions, 0 deletions
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 |