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 0d257cd170362e14de00696aa242c34ffc63223f..9b349eee3cc4517b86a6f700e447cada6e3e4a3f 100644 (file)
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -840,6 +840,7 @@ 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 577fe1e752e3a38a7c580eeaf83d5ae59b2a8288..a9a98e6b9cf41145aee1ccee049f4ae806729b6a 100644 (file)
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -706,7 +706,17 @@ 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 de337d83d75ea996cf38863b40bad8234e9570b7..a36a84bd55e7bfbe9f161fdf3ec133465d2896a0 100644 (file)
--- a/src/test/regress/expected/identity.out
+++ b/src/test/regress/expected/identity.out
@@ -399,3 +399,16 @@ CREATE TABLE itest_child PARTITION OF itest_parent (
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  identity columns are not supported on partitions
 DROP TABLE itest_parent;
+-- 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 40aaf6163d9dd1b0c669f535f92252b4768fe3b3..e93bc7b7e4dbd180ef1ec71fb21a5ab0a8ce471a 100644 (file)
--- a/src/test/regress/sql/identity.sql
+++ b/src/test/regress/sql/identity.sql
@@ -254,3 +254,12 @@ CREATE TABLE itest_child PARTITION OF itest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE itest_parent;
+
+-- 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;