From f673e7416f3a18a1ad9471d696782206114532f7 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Fri, 19 Jun 2026 17:14:33 -0700
Subject: [PATCH] Add create table execute-write template (#2794)

Add a Create table starter template to the execute-write page, alongside the existing table-specific insert/update/delete templates.

Keep template button clicks in-page by updating CodeMirror and the URL without collapsing the template controls.

Refresh schema metadata after successful schema-changing execute-write statements so newly created tables appear immediately.
---
 datasette/app.py                       |   7 +-
 datasette/templates/execute_write.html |  71 ++++++++++----
 datasette/views/execute_write.py       |  33 +++++++
 tests/test_queries.py                  | 127 +++++++++++++++++++++++++
 4 files changed, 220 insertions(+), 18 deletions(-)

diff --git a/datasette/app.py b/datasette/app.py
index 545a65c8..139e4c34 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -625,9 +625,12 @@ class Datasette:
                 return action
         return None
 
-    async def refresh_schemas(self):
+    async def refresh_schemas(self, *, force=False):
         # Throttle schema refreshes to at most once per second
-        if time.monotonic() - getattr(self, "_last_schema_refresh", 0) < 1.0:
+        if (
+            not force
+            and time.monotonic() - getattr(self, "_last_schema_refresh", 0) < 1.0
+        ):
             return
         self._last_schema_refresh = time.monotonic()
         if self._refresh_schemas_lock.locked():
diff --git a/datasette/templates/execute_write.html b/datasette/templates/execute_write.html
index 949850ed..0d0a9931 100644
--- a/datasette/templates/execute_write.html
+++ b/datasette/templates/execute_write.html
@@ -93,20 +93,25 @@ form.sql.core input[data-execute-write-submit]:disabled {
 {% endif %}
 
 <form class="sql core" action="{{ urls.database(database) }}/-/execute-write" method="post" data-analyze-url="{{ urls.database(database) }}/-/execute-write/analyze">
-    {% if write_template_tables %}
+    {% if write_create_table_template_sql or write_template_tables %}
         <div class="execute-write-template-menu">
             <details>
                 <summary>Start with a template</summary>
                 <p class="execute-write-template-controls">
-                    <label for="execute-write-template-table">Table</label>
-                    <select id="execute-write-template-table">
-                        {% for table_name, table in write_template_tables|dictsort %}
-                            <option value="{{ table_name }}"{% for operation, template_sql in table.templates|dictsort %} data-template-{{ operation }}-sql="{{ template_sql }}"{% endfor %}>{{ table_name }}</option>
+                    {% if write_create_table_template_sql %}
+                        <button type="button" data-sql-template="create" data-template-sql="{{ write_create_table_template_sql }}">Create table</button>
+                    {% endif %}
+                    {% if write_template_tables %}
+                        <label for="execute-write-template-table">{% if write_create_table_template_sql %}or table:{% else %}Table{% endif %}</label>
+                        <select id="execute-write-template-table">
+                            {% for table_name, table in write_template_tables|dictsort %}
+                                <option value="{{ table_name }}"{% for operation, template_sql in table.templates|dictsort %} data-template-{{ operation }}-sql="{{ template_sql }}"{% endfor %}>{{ table_name }}</option>
+                            {% endfor %}
+                        </select>
+                        {% for operation in write_template_operations %}
+                            <button type="button" data-sql-template="{{ operation.name }}">{{ operation.label }}</button>
                         {% endfor %}
-                    </select>
-                    {% for operation in write_template_operations %}
-                        <button type="button" data-sql-template="{{ operation.name }}">{{ operation.label }}</button>
-                    {% endfor %}
+                    {% endif %}
                 </p>
             </details>
         </div>
@@ -252,11 +257,12 @@ window.addEventListener("DOMContentLoaded", () => {
 });
 </script>
 
-{% if write_template_tables %}
+{% if write_create_table_template_sql or write_template_tables %}
 <script>
 window.addEventListener("DOMContentLoaded", () => {
   const tableSelect = document.querySelector("#execute-write-template-table");
   const templateButtons = document.querySelectorAll("[data-sql-template]");
+  const sqlInput = document.querySelector("textarea#sql-editor");
 
   function dataKey(operation) {
     return `template${operation.charAt(0).toUpperCase()}${operation.slice(1)}Sql`;
@@ -266,26 +272,59 @@ window.addEventListener("DOMContentLoaded", () => {
     return tableSelect ? tableSelect.options[tableSelect.selectedIndex] : null;
   }
 
-  function templateSql(operation) {
+  function templateSql(button) {
+    if (button.dataset.templateSql) {
+      return button.dataset.templateSql;
+    }
+    const operation = button.dataset.sqlTemplate;
     const option = selectedOption();
     return option ? option.dataset[dataKey(operation)] || "" : "";
   }
 
   function updateTemplateButtons() {
     templateButtons.forEach((button) => {
-      button.hidden = !templateSql(button.dataset.sqlTemplate);
+      button.hidden = !templateSql(button);
     });
   }
 
+  function updateSqlUrl(sql) {
+    if (!window.history || !window.history.replaceState) {
+      return;
+    }
+    const url = new URL(window.location.href);
+    url.searchParams.set("sql", sql);
+    window.history.replaceState(null, "", url.toString());
+  }
+
+  function setEditorSql(sql) {
+    if (window.editor) {
+      window.editor.dispatch({
+        changes: {
+          from: 0,
+          to: window.editor.state.doc.length,
+          insert: sql,
+        },
+        selection: { anchor: sql.length },
+      });
+      window.editor.focus();
+      if (sqlInput) {
+        sqlInput.value = sql;
+      }
+    } else if (sqlInput) {
+      sqlInput.value = sql;
+      sqlInput.dispatchEvent(new Event("input", { bubbles: true }));
+      sqlInput.focus();
+    }
+    updateSqlUrl(sql);
+  }
+
   templateButtons.forEach((button) => {
     button.addEventListener("click", () => {
-      const sql = templateSql(button.dataset.sqlTemplate);
+      const sql = templateSql(button);
       if (!sql) {
         return;
       }
-      const url = new URL(window.location.href);
-      url.searchParams.set("sql", sql);
-      window.location.href = url.toString();
+      setEditorSql(sql);
     });
   });
   if (tableSelect) {
diff --git a/datasette/views/execute_write.py b/datasette/views/execute_write.py
index 2817f56e..b7e8288e 100644
--- a/datasette/views/execute_write.py
+++ b/datasette/views/execute_write.py
@@ -31,6 +31,15 @@ WRITE_TEMPLATE_LABELS = {
     "delete": "Delete rows",
 }
 WRITE_TEMPLATE_OPERATIONS = tuple(WRITE_TEMPLATE_LABELS)
+CREATE_TABLE_TEMPLATE_SQL = "\n".join(
+    (
+        "create table new_table (",
+        "  id integer primary key,",
+        "  name text",
+        "  -- created text default (datetime('now'))",
+        ")",
+    )
+)
 
 
 def _parameter_names(columns):
@@ -207,6 +216,23 @@ def _write_template_operations(write_template_tables):
     return operations
 
 
+async def _create_table_template_sql(datasette, db, actor):
+    if await datasette.allowed(
+        action="create-table",
+        resource=DatabaseResource(db.name),
+        actor=actor,
+    ):
+        return CREATE_TABLE_TEMPLATE_SQL
+    return None
+
+
+def _analysis_changes_schema(analysis):
+    return any(
+        operation.operation in {"create", "alter", "drop"}
+        for operation in analysis.operations
+    )
+
+
 class ExecuteWriteView(BaseView):
     name = "execute-write"
     has_json_alternate = False
@@ -241,6 +267,9 @@ class ExecuteWriteView(BaseView):
             self.ds, db, table_columns, hidden_table_names, request.actor
         )
         write_template_operations = _write_template_operations(write_template_tables)
+        write_create_table_template_sql = await _create_table_template_sql(
+            self.ds, db, request.actor
+        )
         if sql and analysis_error is None:
             try:
                 parameter_names = _derived_query_parameters(sql)
@@ -302,6 +331,7 @@ class ExecuteWriteView(BaseView):
                 "table_columns": table_columns,
                 "write_template_tables": write_template_tables,
                 "write_template_operations": write_template_operations,
+                "write_create_table_template_sql": write_create_table_template_sql,
                 "save_query_url": save_query_url,
                 "save_query_base_url": save_query_base_url,
             },
@@ -387,6 +417,9 @@ class ExecuteWriteView(BaseView):
                 status=400,
             )
 
+        if _analysis_changes_schema(analysis):
+            await self.ds.refresh_schemas(force=True)
+
         if cursor.rowcount == -1:
             message = "Query executed"
         else:
diff --git a/tests/test_queries.py b/tests/test_queries.py
index 0354f73a..c3c0b9db 100644
--- a/tests/test_queries.py
+++ b/tests/test_queries.py
@@ -14,6 +14,15 @@ from datasette.utils.sqlite import sqlite3, supports_returning
 requires_sqlite_returning = pytest.mark.skipif(
     not supports_returning(), reason="SQLite does not support RETURNING"
 )
+EXPECTED_CREATE_TABLE_TEMPLATE_SQL = "\n".join(
+    (
+        "create table new_table (",
+        "  id integer primary key,",
+        "  name text",
+        "  -- created text default (datetime('now'))",
+        ")",
+    )
+)
 
 
 def _template_option_attributes(html, table):
@@ -29,6 +38,16 @@ def _template_sql(html, table, operation):
     return unescape(match.group(1))
 
 
+def _template_button_sql(html, operation):
+    soup = Soup(html, "html.parser")
+    button = soup.select_one('button[data-sql-template="{}"]'.format(operation))
+    assert button, "Could not find {} template button".format(operation)
+    assert button.get(
+        "data-template-sql"
+    ), "Could not find SQL for {} template button".format(operation)
+    return button["data-template-sql"]
+
+
 async def add_numbered_queries(ds, database, count):
     for i in range(1, count + 1):
         await ds.add_query(
@@ -1645,6 +1664,14 @@ async def test_execute_write_get_prepopulates_without_executing():
     )
     assert "<h2>Query operations</h2>" in response.text
     assert "<summary>Start with a template</summary>" in response.text
+    assert 'data-sql-template="create"' in response.text
+    assert _template_button_sql(response.text, "create") == (
+        EXPECTED_CREATE_TABLE_TEMPLATE_SQL
+    )
+    assert ">Create table</button>" in response.text
+    assert '<label for="execute-write-template-table">or table:</label>' in (
+        response.text
+    )
     assert '<option value="dogs"' in response.text
     assert "data-template-insert-sql=" in response.text
     assert 'data-sql-template="insert"' in response.text
@@ -1660,6 +1687,9 @@ async def test_execute_write_get_prepopulates_without_executing():
     assert 'addEventListener("paste"' in response.text
     assert "setupSqlParameterRefresh" in response.text
     assert "datasetteSqlAnalysis.renderAnalysis" in response.text
+    assert "window.editor.dispatch" in response.text
+    assert "window.history.replaceState" in response.text
+    assert "window.location.href = url.toString();" not in response.text
     assert "input[data-execute-write-submit]:disabled" in response.text
     assert (
         'data-execute-write-disabled-reason aria-live="polite" hidden' in response.text
@@ -1813,6 +1843,7 @@ async def test_execute_write_templates_are_filtered_by_permission_and_server_gen
     assert '<option value="dogs"' in writer_response.text
     assert '<option value="manual"' in writer_response.text
     assert '<option value="cats"' not in writer_response.text
+    assert 'data-sql-template="create"' not in writer_response.text
     assert "function insertSql(" not in writer_response.text
     assert "function updateSql(" not in writer_response.text
     assert "function deleteSql(" not in writer_response.text
@@ -1842,6 +1873,7 @@ async def test_execute_write_templates_are_filtered_by_permission_and_server_gen
     assert 'data-sql-template="delete"' in deleter_response.text
     assert 'data-sql-template="insert"' not in deleter_response.text
     assert 'data-sql-template="update"' not in deleter_response.text
+    assert 'data-sql-template="create"' not in deleter_response.text
 
     assert viewer_response.status_code == 200
     assert "<summary>Start with a template</summary>" not in viewer_response.text
@@ -1851,6 +1883,101 @@ async def test_execute_write_templates_are_filtered_by_permission_and_server_gen
     assert "data-template-delete-sql" not in viewer_response.text
 
 
+@pytest.mark.asyncio
+async def test_execute_write_create_table_template_is_filtered_by_permission():
+    ds = Datasette(
+        memory=True,
+        default_deny=True,
+        config={
+            "databases": {
+                "data": {
+                    "permissions": {
+                        "view-database": {"id": ["creator", "editor", "both"]},
+                        "execute-write-sql": {"id": ["creator", "editor", "both"]},
+                        "create-table": {"id": ["creator", "both"]},
+                    },
+                    "tables": {
+                        "dogs": {
+                            "permissions": {
+                                "view-table": {"id": ["editor", "both"]},
+                                "insert-row": {"id": ["editor", "both"]},
+                                "update-row": {"id": ["editor", "both"]},
+                                "delete-row": {"id": ["editor", "both"]},
+                            }
+                        },
+                    },
+                }
+            }
+        },
+    )
+    db = ds.add_memory_database("execute_write_create_template", name="data")
+    await db.execute_write("create table dogs (id integer primary key, name text)")
+    await ds.invoke_startup()
+
+    creator_response = await ds.client.get(
+        "/data/-/execute-write", actor={"id": "creator"}
+    )
+    editor_response = await ds.client.get(
+        "/data/-/execute-write", actor={"id": "editor"}
+    )
+    both_response = await ds.client.get("/data/-/execute-write", actor={"id": "both"})
+
+    assert creator_response.status_code == 200
+    assert "<summary>Start with a template</summary>" in creator_response.text
+    assert _template_button_sql(creator_response.text, "create") == (
+        EXPECTED_CREATE_TABLE_TEMPLATE_SQL
+    )
+    assert "There are no tables that you can currently edit." not in (
+        creator_response.text
+    )
+    assert 'id="execute-write-template-table"' not in creator_response.text
+    assert 'data-sql-template="insert"' not in creator_response.text
+    assert 'data-sql-template="update"' not in creator_response.text
+    assert 'data-sql-template="delete"' not in creator_response.text
+
+    assert editor_response.status_code == 200
+    assert 'data-sql-template="create"' not in editor_response.text
+    assert '<label for="execute-write-template-table">Table</label>' in (
+        editor_response.text
+    )
+    assert 'data-sql-template="insert"' in editor_response.text
+    assert 'data-sql-template="update"' in editor_response.text
+    assert 'data-sql-template="delete"' in editor_response.text
+
+    assert both_response.status_code == 200
+    assert _template_button_sql(both_response.text, "create") == (
+        EXPECTED_CREATE_TABLE_TEMPLATE_SQL
+    )
+    assert '<label for="execute-write-template-table">or table:</label>' in (
+        both_response.text
+    )
+    assert 'data-sql-template="insert"' in both_response.text
+    assert 'data-sql-template="update"' in both_response.text
+    assert 'data-sql-template="delete"' in both_response.text
+
+
+@pytest.mark.asyncio
+async def test_execute_write_create_table_refreshes_template_tables():
+    ds = Datasette(memory=True, default_deny=True)
+    ds.root_enabled = True
+    db = ds.add_memory_database("execute_write_create_template_refresh", name="data")
+    await ds.invoke_startup()
+
+    response = await ds.client.post(
+        "/data/-/execute-write",
+        actor={"id": "root"},
+        data={"sql": "create table selectable (id integer primary key, name text)"},
+    )
+
+    assert response.status_code == 200
+    assert "Query executed" in response.text
+    assert '<option value="selectable"' in response.text
+    assert _template_sql(response.text, "selectable", "insert") == (
+        'insert into "selectable" (\n' '  "name"\n' ")\n" "values (\n" "  :name\n" ")"
+    )
+    assert await db.table_exists("selectable")
+
+
 @pytest.mark.asyncio
 async def test_execute_write_analyze_endpoint_uses_sql_only():
     ds = Datasette(memory=True, default_deny=True)