db.iterdump() method uses sqlite-dump if available

.github/workflows/test.yml

@@ -37,7 +37,7 @@ jobs:
       run: sudo apt-get install libsqlite3-mod-spatialite
     - name: On macOS with Python 3.10 test with sqlean.py
       if: matrix.os == 'macos-latest' && matrix.python-version == '3.10'
-      run: pip install sqlean.py
+      run: pip install sqlean.py sqlite-dump
     - name: Build extension for --load-extension test
       if: matrix.os == 'ubuntu-latest'
       run: |-

docs/installation.rst

@@ -60,6 +60,12 @@ To install ``sqlean.py`` (which has compiled binary wheels available for all maj
 
     sqlite-utils install sqlean.py
 
+``pysqlite3`` and ``sqlean.py`` do not provide implementations of the ``.iterdump()`` method. To use that method (see :ref:`python_api_itedump`) or the ``sqlite-utils dump`` command you should also install the ``sqlite-dump`` package:
+
+.. code-block:: bash
+
+    sqlite-utils install sqlite-dump
+
 .. _installation_completion:
 
 Setting up shell completion

docs/python-api.rst

@@ -1779,6 +1779,25 @@ The ``db.sqlite_version`` property returns a tuple of integers representing the
     >>> db.sqlite_version
     (3, 36, 0)
 
+.. _python_api_itedump:
+
+Dumping the database to SQL
+===========================
+
+The ``db.iterdump()`` method returns a sequence of SQL strings representing a complete dump of the database. Use it like this:
+
+.. code-block:: python
+
+    full_sql = "".join(db.iterdump())
+
+This uses the `sqlite3.Connection.iterdump() <https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.iterdump>`__ method.
+
+If you are using ``pysqlite3`` or ``sqlean.py`` the underlying method may be missing. If you install the `sqlite-dump <https://pypi.org/project/sqlite-dump/>`__ package then the ``db.iterdump()`` method will use that implementation instead:
+
+.. code-block:: bash
+
+    pip install sqlite-dump
+
 .. _python_api_introspection:
 
 Introspecting tables and views

mypy.ini

@@ -1,4 +1,4 @@
 [mypy]
 
-[mypy-pysqlite3,sqlean]
+[mypy-pysqlite3,sqlean,sqlite_dump]
 ignore_missing_imports = True

sqlite_utils/cli.py

@@ -395,7 +395,7 @@ def dump(path, load_extension):
     """
     db = sqlite_utils.Database(path)
     _load_extensions(db, load_extension)
-    for line in db.conn.iterdump():
+    for line in db.iterdump():
         click.echo(line)
 
 
@@ -1893,7 +1893,7 @@ def memory(
         return
 
     if dump:
-        for line in db.conn.iterdump():
+        for line in db.iterdump():
             click.echo(line)
         return
 
@@ -1903,7 +1903,7 @@ def memory(
 
     if save:
         db2 = sqlite_utils.Database(save)
-        for line in db.conn.iterdump():
+        for line in db.iterdump():
             db2.execute(line)
         return
 

sqlite_utils/db.py

@@ -38,6 +38,12 @@ from typing import (
 )
 import uuid
 
+try:
+    from sqlite_dump import iterdump
+except ImportError:
+    iterdump = None
+
+
 SQLITE_MAX_VARS = 999
 
 _quote_fts_re = re.compile(r'\s+|(".*?")')
@@ -1149,6 +1155,18 @@ class Database:
             sql += " [{}]".format(name)
         self.execute(sql)
 
+    def iterdump(self) -> Generator[str, None, None]:
+        "A sequence of strings representing a SQL dump of the database"
+        if iterdump:
+            yield from iterdump(self.conn)
+        else:
+            try:
+                yield from self.conn.iterdump()
+            except AttributeError:
+                raise AttributeError(
+                    "conn.iterdump() not found - try pip install sqlite-dump"
+                )
+
     def init_spatialite(self, path: Optional[str] = None) -> bool:
         """
         The ``init_spatialite`` method will load and initialize the SpatiaLite extension.

tests/test_analyze_tables.py

@@ -135,7 +135,8 @@ def test_analyze_column(db_to_analyze, column, extra_kwargs, expected):
 def db_to_analyze_path(db_to_analyze, tmpdir):
     path = str(tmpdir / "test.db")
     db = sqlite3.connect(path)
-    db.executescript("\n".join(db_to_analyze.conn.iterdump()))
+    sql = "\n".join(db_to_analyze.iterdump())
+    db.executescript(sql)
     return path
 
 

tests/test_cli_memory.py

@@ -164,9 +164,9 @@ def test_memory_dump(extra_args):
         input="id,name\n1,Cleo\n2,Bants",
     )
     assert result.exit_code == 0
-    assert result.output.strip() == (
+    expected = (
         "BEGIN TRANSACTION;\n"
-        'CREATE TABLE "stdin" (\n'
+        'CREATE TABLE IF NOT EXISTS "stdin" (\n'
         "   [id] INTEGER,\n"
         "   [name] TEXT\n"
         ");\n"
@@ -176,6 +176,9 @@ def test_memory_dump(extra_args):
         "CREATE VIEW t AS select * from [stdin];\n"
         "COMMIT;"
     )
+    # Using sqlite-dump it won't have IF NOT EXISTS
+    expected_alternative = expected.replace("IF NOT EXISTS ", "")
+    assert result.output.strip() in (expected, expected_alternative)
 
 
 @pytest.mark.parametrize("extra_args", ([], ["select 1"]))