Forbid marking an identity column as nullable.

GENERATED ALWAYS AS IDENTITY implies NOT NULL, but the code failed
to complain if you overrode that with "GENERATED ALWAYS AS IDENTITY
NULL".  One might think the old behavior was a feature, but it was
inconsistent because the outcome varied depending on the order of
the clauses, so it seems to have been just an oversight.

Per bug #16913 from Pavel Boev.  Back-patch to v10 where identity
columns were introduced.

Vik Fearing (minor tweaks by me)

Discussion: https://postgr.es/m/16913-3b5198410f67d8c6@postgresql.org

diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index ca0855d71316e50819f792f04327d102cd315fc8..e56c4af9b1747d2ec24214628e260391fbeaf1be 100644 (file)
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -839,6 +839,7 @@ WITH ( MODULUS numeric_literal, REM
       column.  It will have an implicit sequence attached to it
       and the column in new rows will automatically have values from the
       sequence assigned to it.
+      Such a column is implicitly NOT NULL.
      
 
      

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index c4076a3868ba77ea6d3b308eb41efeccbc6e6a28..49a898b64617810583baa9759ee98ba019717ecf 100644 (file)
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -716,7 +716,17 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 
                    column->identity = constraint->generated_when;
                    saw_identity = true;
+
+                   /* An identity column is implicitly NOT NULL */
+                   if (saw_nullable && !column->is_not_null)
+                       ereport(ERROR,
+                               (errcode(ERRCODE_SYNTAX_ERROR),
+                                errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
+                                       column->colname, cxt->relation->relname),
+                                parser_errposition(cxt->pstate,
+                                                   constraint->location)));
                    column->is_not_null = true;
+                   saw_nullable = true;
                    break;
                }
 

diff --git a/src/test/regress/expected/identity.out b/src/test/regress/expected/identity.out
index 2238f896f9a483040c373539c71b47b5196d1d4a..069a42b70cfd5eee4acc0f32759e87468a46aaa8 100644 (file)
--- a/src/test/regress/expected/identity.out
+++ b/src/test/regress/expected/identity.out
@@ -491,3 +491,16 @@ CREATE TABLE itest14 (id serial);
 ALTER TABLE itest14 ALTER id DROP DEFAULT;
 ALTER TABLE itest14 ALTER id ADD GENERATED BY DEFAULT AS IDENTITY;
 INSERT INTO itest14 (id) VALUES (DEFAULT);
+-- Identity columns must be NOT NULL (cf bug #16913)
+CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NULL); -- fail
+ERROR:  conflicting NULL/NOT NULL declarations for column "id" of table "itest15"
+LINE 1: ...ABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NULL);
+                                                                 ^
+CREATE TABLE itest15 (id integer NULL GENERATED ALWAYS AS IDENTITY); -- fail
+ERROR:  conflicting NULL/NOT NULL declarations for column "id" of table "itest15"
+LINE 1: CREATE TABLE itest15 (id integer NULL GENERATED ALWAYS AS ID...
+                                              ^
+CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NOT NULL);
+DROP TABLE itest15;
+CREATE TABLE itest15 (id integer NOT NULL GENERATED ALWAYS AS IDENTITY);
+DROP TABLE itest15;

diff --git a/src/test/regress/sql/identity.sql b/src/test/regress/sql/identity.sql
index d4bc29ab5c30072efbfcb7d8a5f0b7a820d5c55a..6e5cb1b9e0959c45f643ceed9f98487f4dcabdea 100644 (file)
--- a/src/test/regress/sql/identity.sql
+++ b/src/test/regress/sql/identity.sql
@@ -323,3 +323,12 @@ CREATE TABLE itest14 (id serial);
 ALTER TABLE itest14 ALTER id DROP DEFAULT;
 ALTER TABLE itest14 ALTER id ADD GENERATED BY DEFAULT AS IDENTITY;
 INSERT INTO itest14 (id) VALUES (DEFAULT);
+
+-- Identity columns must be NOT NULL (cf bug #16913)
+
+CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NULL); -- fail
+CREATE TABLE itest15 (id integer NULL GENERATED ALWAYS AS IDENTITY); -- fail
+CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NOT NULL);
+DROP TABLE itest15;
+CREATE TABLE itest15 (id integer NOT NULL GENERATED ALWAYS AS IDENTITY);
+DROP TABLE itest15;