Ticket #4432: django-4432.2.diff

django/db/backends/postgresql/base.py

@@ -219 +219 @@
     from django.db import models
     output = []
     for model in model_list:
+        # Use `coalesce` to set the sequence for each model to the max pk value if there are records,
+        # or 1 if there are none. Set the `is_called` property (the third argument to `setval`) to true
+        # if there are records (as the max pk value is already in use), otherwise set it to false.
         for f in model._meta.fields:
             if isinstance(f, models.AutoField):
-                output.append("%s setval('%s', (%s max(%s) %s %s));" % \
+                output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                     (style.SQL_KEYWORD('SELECT'),
                     style.SQL_FIELD(quote_name('%s_%s_seq' % (model._meta.db_table, f.column))),
-                    style.SQL_KEYWORD('SELECT'),
                     style.SQL_FIELD(quote_name(f.column)),
+                    style.SQL_FIELD(quote_name(f.column)),
+                    style.SQL_KEYWORD('IS NOT'),
                     style.SQL_KEYWORD('FROM'),
                     style.SQL_TABLE(quote_name(model._meta.db_table))))
                 break # Only one AutoField is allowed per model, so don't bother continuing.
         for f in model._meta.many_to_many:
-            output.append("%s setval('%s', (%s max(%s) %s %s));" % \
+            output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                 (style.SQL_KEYWORD('SELECT'),
                 style.SQL_FIELD(quote_name('%s_id_seq' % f.m2m_db_table())),
-                style.SQL_KEYWORD('SELECT'),
                 style.SQL_FIELD(quote_name('id')),
+                style.SQL_FIELD(quote_name('id')),
+                style.SQL_KEYWORD('IS NOT'),
                 style.SQL_KEYWORD('FROM'),
                 style.SQL_TABLE(f.m2m_db_table())))
     return output

django/db/backends/postgresql_psycopg2/base.py

@@ -176 +176 @@
     from django.db import models
     output = []
     for model in model_list:
+        # Use `coalesce` to set the sequence for each model to the max pk value if there are records,
+        # or 1 if there are none. Set the `is_called` property (the third argument to `setval`) to true
+        # if there are records (as the max pk value is already in use), otherwise set it to false.
         for f in model._meta.fields:
             if isinstance(f, models.AutoField):
-                output.append("%s setval('%s', (%s max(%s) %s %s));" % \
+                output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                     (style.SQL_KEYWORD('SELECT'),
                     style.SQL_FIELD(quote_name('%s_%s_seq' % (model._meta.db_table, f.column))),
-                    style.SQL_KEYWORD('SELECT'),
                     style.SQL_FIELD(quote_name(f.column)),
+                    style.SQL_FIELD(quote_name(f.column)),
+                    style.SQL_KEYWORD('IS NOT'),
                     style.SQL_KEYWORD('FROM'),
                     style.SQL_TABLE(quote_name(model._meta.db_table))))
                 break # Only one AutoField is allowed per model, so don't bother continuing.
         for f in model._meta.many_to_many:
-            output.append("%s setval('%s', (%s max(%s) %s %s));" % \
+            output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                 (style.SQL_KEYWORD('SELECT'),
                 style.SQL_FIELD(quote_name('%s_id_seq' % f.m2m_db_table())),
-                style.SQL_KEYWORD('SELECT'),
                 style.SQL_FIELD(quote_name('id')),
+                style.SQL_FIELD(quote_name('id')),
+                style.SQL_KEYWORD('IS NOT'),
                 style.SQL_KEYWORD('FROM'),
                 style.SQL_TABLE(f.m2m_db_table())))
     return output