Support SQLite WITHOUT ROWID tables

This adds support for creating tables WITHOUT ROWID in the SQLite
dialect. WITHOUT ROWID tables were introduced in SQLite version 3.8.2
(2013-12-06). They do not use an implicit rowid column as the primary
key. This may result in space and performance savings for tables without
INTEGER primary keys and tables with composite primary keys. For more
information about this feature, see the sqlite documentation [1].

[1] https://www.sqlite.org/withoutrowid.html

Fixes: #5685
### Checklist
This pull request is:

- [x] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

Closes: #5686
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5686
Pull-request-sha: 2b44782d1b3d858e31ce1ff8e08e197af37344d8

Change-Id: Ifcf727b0c07c90e267b79828a8e3fd7a8260a074

diff --git a/doc/build/changelog/unreleased_13/5685.rst b/doc/build/changelog/unreleased_13/5685.rst
new file mode 100644 (file)
index 0000000..6f98cfa
--- /dev/null
+++ b/doc/build/changelog/unreleased_13/5685.rst
@@ -0,0 +1,6 @@
+.. change::
+    :tags: sqlite, usecase
+    :tickets: 5685
+
+    Added ``sqlite_with_rowid=False`` dialect keyword to enable creating
+    tables as ``CREATE TABLE … WITHOUT ROWID``. Patch courtesy Sean Anderson.

diff --git a/lib/sqlalchemy/dialects/sqlite/base.py b/lib/sqlalchemy/dialects/sqlite/base.py
index 5efd0d9c991edc3fd7dc32afd1ab24f65da2fd4f..aead9914794de474efe37c3ea53260fd57e7dba4 100644 (file)
--- a/lib/sqlalchemy/dialects/sqlite/base.py
+++ b/lib/sqlalchemy/dialects/sqlite/base.py
@@ -583,6 +583,21 @@ or on a per-:class:`_engine.Engine` basis::
 When using the per-:class:`_engine.Engine` execution option, note that
 **Core and ORM queries that use UNION may not function properly**.
 
+SQLite-specific table options
+-----------------------------
+
+One option for CREATE TABLE is supported directly by the SQLite
+dialect in conjunction with the :class:`_schema.Table` construct:
+
+* ``WITHOUT ROWID``::
+
+    Table("some_table", metadata, ..., sqlite_with_rowid=False)
+
+.. seealso::
+
+    `SQLite CREATE TABLE options
+    <https://www.sqlite.org/lang_createtable.html>`_
+
 """  # noqa
 
 import datetime
@@ -1259,6 +1274,11 @@ class SQLiteDDLCompiler(compiler.DDLCompiler):
 
         return text
 
+    def post_create_table(self, table):
+        if table.dialect_options["sqlite"]["with_rowid"] is False:
+            return "\n WITHOUT ROWID"
+        return ""
+
 
 class SQLiteTypeCompiler(compiler.GenericTypeCompiler):
     def visit_large_binary(self, type_, **kw):
@@ -1466,7 +1486,13 @@ class SQLiteDialect(default.DefaultDialect):
     isolation_level = None
 
     construct_arguments = [
-        (sa_schema.Table, {"autoincrement": False}),
+        (
+            sa_schema.Table,
+            {
+                "autoincrement": False,
+                "with_rowid": True,
+            },
+        ),
         (sa_schema.Index, {"where": None}),
         (
             sa_schema.Column,

diff --git a/test/dialect/test_sqlite.py b/test/dialect/test_sqlite.py
index d06cd48f5fe63e4bd5c1cdef1ad005cd09a79a7d..57529aeb6d7783f1041d296efbbaf94cedab609d 100644 (file)
--- a/test/dialect/test_sqlite.py
+++ b/test/dialect/test_sqlite.py
@@ -1161,6 +1161,16 @@ class SQLTest(fixtures.TestBase, AssertsCompiledSQL):
             ),
         )
 
+    def test_create_table_without_rowid(self):
+        m = MetaData()
+        tbl = Table(
+            "atable", m, Column("id", Integer), sqlite_with_rowid=False
+        )
+        self.assert_compile(
+            schema.CreateTable(tbl),
+            "CREATE TABLE atable (id INTEGER) WITHOUT ROWID",
+        )
+
 
 class OnConflictDDLTest(fixtures.TestBase, AssertsCompiledSQL):