database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-02 04:21:28 +03:00
Code Activity

Generated columns

Browse Source 
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
This commit is contained in:
Peter Eisentraut
2019-03-30 08:13:09 +01:00
parent 6b8b5364dd
commit fc22b6623b
84 changed files with 3067 additions and 157 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/backend/parser/analyze.c
View File

@@ -2287,6 +2287,7 @@ transformUpdateTargetList(ParseState *pstate, List *origTlist)
RangeTblEntry *target_rte;
ListCell *orig_tl;
ListCell *tl;
TupleDesc tupdesc = pstate->p_target_relation->rd_att;
tlist = transformTargetList(pstate, origTlist,
EXPR_KIND_UPDATE_SOURCE);
@@ -2345,6 +2346,32 @@ transformUpdateTargetList(ParseState *pstate, List *origTlist)
if (orig_tl != NULL)
elog(ERROR, "UPDATE target count mismatch --- internal error");
/*
* Record in extraUpdatedCols generated columns referencing updated base
* columns.
*/
if (tupdesc->constr &&
tupdesc->constr->has_generated_stored)
{
for (int i = 0; i < tupdesc->constr->num_defval; i++)
{
AttrDefault defval = tupdesc->constr->defval[i];
Node *expr;
Bitmapset *attrs_used = NULL;
/* skip if not generated column */
if (!TupleDescAttr(tupdesc, defval.adnum - 1)->attgenerated)
continue;
expr = stringToNode(defval.adbin);
pull_varattnos(expr, 1, &attrs_used);
if (bms_overlap(target_rte->updatedCols, attrs_used))
target_rte->extraUpdatedCols = bms_add_member(target_rte->extraUpdatedCols,
defval.adnum - FirstLowInvalidHeapAttributeNumber);
}
}
return tlist;
}