From d16097231c5e51ea857b58c700f97a17b68dc583 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Sun, 3 May 2020 08:36:29 -0700
Subject: [PATCH] Added sqlite-utils create-view command, closes #107

---
 docs/cli.rst        | 15 +++++++++++
 sqlite_utils/cli.py | 32 ++++++++++++++++++++++
 tests/test_cli.py   | 66 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 113 insertions(+)

diff --git a/docs/cli.rst b/docs/cli.rst
index 7c0c9c5..40ac963 100644
--- a/docs/cli.rst
+++ b/docs/cli.rst
@@ -401,6 +401,21 @@ You can specify foreign key relationships between the tables you are creating us
 
 If a table with the same name already exists, you will get an error. You can choose to silently ignore this error with ``--ignore``, or you can replace the existing table with a new, empty table using ``--replace``.
 
+
+.. _cli_create_view:
+
+Creating views
+==============
+
+You can create a view using the ``create-view`` command::
+
+    $ sqlite-utils create-view mydb.db version "select sqlite_version()"
+
+    $ sqlite-utils mydb.db "select * from version"
+    [{"sqlite_version()": "3.31.1"}]
+
+Use ``--replace`` to replace an existing view of the same name, and ``--ignore`` to do nothing if a view already exists.
+
 .. _cli_add_column:
 
 Adding columns
diff --git a/sqlite_utils/cli.py b/sqlite_utils/cli.py
index 8a7fabb..f1b5ac6 100644
--- a/sqlite_utils/cli.py
+++ b/sqlite_utils/cli.py
@@ -594,6 +594,38 @@ def create_table(path, table, columns, pk, not_null, default, fk, ignore, replac
     )
 
 
+@cli.command(name="create-view")
+@click.argument(
+    "path",
+    type=click.Path(file_okay=True, dir_okay=False, allow_dash=False),
+    required=True,
+)
+@click.argument("view")
+@click.argument("select")
+@click.option(
+    "--ignore", is_flag=True, help="If view already exists, do nothing",
+)
+@click.option(
+    "--replace", is_flag=True, help="If view already exists, replace it",
+)
+def create_view(path, view, select, ignore, replace):
+    "Create a view for the provided SELECT query"
+    db = sqlite_utils.Database(path)
+    # Does view already exist?
+    if view in db.view_names():
+        if ignore:
+            return
+        elif replace:
+            db[view].drop()
+        else:
+            raise click.ClickException(
+                'View "{}" already exists. Use --replace to delete and replace it.'.format(
+                    view
+                )
+            )
+    db.create_view(view, select)
+
+
 @cli.command()
 @click.argument(
     "path",
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 7d653e1..32ea1db 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -999,3 +999,69 @@ def test_create_table_replace():
         )
         assert 0 == result.exit_code
         assert "CREATE TABLE [dogs] (\n   [id] INTEGER\n)" == db["dogs"].schema
+
+
+def test_create_view():
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        db = Database("test.db")
+        result = runner.invoke(
+            cli.cli, ["create-view", "test.db", "version", "select sqlite_version()"]
+        )
+        assert 0 == result.exit_code
+        assert "CREATE VIEW version AS select sqlite_version()" == db["version"].schema
+
+
+def test_create_view_error_if_view_exists():
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        db = Database("test.db")
+        db.create_view("version", "select sqlite_version() + 1")
+        result = runner.invoke(
+            cli.cli, ["create-view", "test.db", "version", "select sqlite_version()"]
+        )
+        assert 1 == result.exit_code
+        assert (
+            'Error: View "version" already exists. Use --replace to delete and replace it.'
+            == result.output.strip()
+        )
+
+
+def test_create_view_ignore():
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        db = Database("test.db")
+        db.create_view("version", "select sqlite_version() + 1")
+        result = runner.invoke(
+            cli.cli,
+            [
+                "create-view",
+                "test.db",
+                "version",
+                "select sqlite_version()",
+                "--ignore",
+            ],
+        )
+        assert 0 == result.exit_code
+        assert (
+            "CREATE VIEW version AS select sqlite_version() + 1" == db["version"].schema
+        )
+
+
+def test_create_view_replace():
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        db = Database("test.db")
+        db.create_view("version", "select sqlite_version() + 1")
+        result = runner.invoke(
+            cli.cli,
+            [
+                "create-view",
+                "test.db",
+                "version",
+                "select sqlite_version()",
+                "--replace",
+            ],
+        )
+        assert 0 == result.exit_code
+        assert "CREATE VIEW version AS select sqlite_version()" == db["version"].schema