diff options
Diffstat (limited to 'src/include/nodes/primnodes.h')
| -rw-r--r-- | src/include/nodes/primnodes.h | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h index dab5c4ff5de..439e4b4a9db 100644 --- a/src/include/nodes/primnodes.h +++ b/src/include/nodes/primnodes.h @@ -1052,15 +1052,13 @@ typedef struct ArrayExpr * than vice versa.) It is important not to assume that length(args) is * the same as the number of columns logically present in the rowtype. * - * colnames provides field names in cases where the names can't easily be - * obtained otherwise. Names *must* be provided if row_typeid is RECORDOID. - * If row_typeid identifies a known composite type, colnames can be NIL to - * indicate the type's cataloged field names apply. Note that colnames can - * be non-NIL even for a composite type, and typically is when the RowExpr - * was created by expanding a whole-row Var. This is so that we can retain - * the column alias names of the RTE that the Var referenced (which would - * otherwise be very difficult to extract from the parsetree). Like the - * args list, colnames is one-for-one with physical fields of the rowtype. + * colnames provides field names if the ROW() result is of type RECORD. + * Names *must* be provided if row_typeid is RECORDOID; but if it is a + * named composite type, colnames will be ignored in favor of using the + * type's cataloged field names, so colnames should be NIL. Like the + * args list, colnames is defined to be one-for-one with physical fields + * of the rowtype (although dropped columns shouldn't appear in the + * RECORD case, so this fine point is currently moot). */ typedef struct RowExpr { |