apply patch for Issue #43 (better SQLite support) by Florian Apolloner

migrate/changeset/databases/sqlite.py

@@ -1,29 +1,52 @@
 from migrate.changeset import ansisql,constraint,exceptions
 from sqlalchemy.databases import sqlite as sa_base
+from sqlalchemy import Table, MetaData
 #import sqlalchemy as sa
 
 SQLiteSchemaGenerator = sa_base.SQLiteSchemaGenerator
 
+class SQLiteHelper(object):
+    def visit_column(self, param):
+        try:
+            table = self._to_table(param.table)
+        except:
+            table = self._to_table(param)
+            raise
+        table_name = self._to_table_name(table)
+        self.append('ALTER TABLE %s RENAME TO migration_tmp' % table_name)
+        self.execute()
+
+        insertion_string = self._modify_table(table, param)
+
+        table.create()
+        self.append(insertion_string % {'table_name': table_name})
+        self.execute()
+        self.append('DROP TABLE migration_tmp')
+        self.execute()
+
 class SQLiteColumnGenerator(SQLiteSchemaGenerator,ansisql.ANSIColumnGenerator):
     pass
-class SQLiteColumnDropper(ansisql.ANSIColumnDropper):
-    def visit_column(self,column):
-        raise exceptions.NotSupportedError("SQLite does not support "
-            "DROP COLUMN; see http://www.sqlite.org/lang_altertable.html")
-class SQLiteSchemaChanger(ansisql.ANSISchemaChanger):
+
+class SQLiteColumnDropper(SQLiteHelper, ansisql.ANSIColumnDropper):
+    def _modify_table(self,table, column):
+        del table.columns[column.name]
+        columns = ','.join([c.name for c in table.columns])
+        return 'INSERT INTO %(table_name)s SELECT ' + columns + ' from migration_tmp'
+
+class SQLiteSchemaChanger(SQLiteHelper, ansisql.ANSISchemaChanger):
     def _not_supported(self,op):
         raise exceptions.NotSupportedError("SQLite does not support "
             "%s; see http://www.sqlite.org/lang_altertable.html"%op)
-    def _visit_column_nullable(self,table_name,col_name,delta):
-        return self._not_supported('ALTER TABLE')
-    def _visit_column_default(self,table_name,col_name,delta):
-        return self._not_supported('ALTER TABLE')
-    def _visit_column_type(self,table_name,col_name,delta):
-        return self._not_supported('ALTER TABLE')
-    def _visit_column_name(self,table_name,col_name,delta):
-        return self._not_supported('ALTER TABLE')
+
+    def _modify_table(self, table, delta):
+        column = table.columns[delta.current_name]
+        for k,v in delta.items():
+            setattr(column, k, v)
+        return 'INSERT INTO %(table_name)s SELECT * from migration_tmp'
+
     def visit_index(self,param):
         self._not_supported('ALTER INDEX')
+
     def _do_quote_column_identifier(self, identifier):
         return '"%s"'%identifier
 
@@ -36,6 +59,7 @@ class SQLiteConstraintGenerator(ansisql.ANSIConstraintGenerator):
         msg = tmpl%(name,tname,cols)
         self.append(msg)
         self.execute()
+
 class SQLiteConstraintDropper(ansisql.ANSIColumnDropper):
     def visit_migrate_primary_key_constraint(self,constraint):
         tmpl = "DROP INDEX %s "

test/changeset/test_changeset.py

@@ -66,10 +66,6 @@ class TestAddDropColumn(fixture.DB):
         self.assertEquals(getattr(self.table.c,col_name),col)
         #drop_column(col,self.table)
         col = getattr(self.table.c,col_name)
-        # SQLite can't do drop column: stop here
-        if self.url.startswith('sqlite://'):
-            self.assertRaises(changeset.exceptions.NotSupportedError,drop_column_func,col)
-            return
         drop_column_func(col)
         assert_numcols(1)
 
@@ -301,18 +297,7 @@ class TestColumnChange(fixture.DB):
         #self.engine.echo=False
         super(TestColumnChange, self)._teardown()
 
-    @fixture.usedb(supported='sqlite')
-    def test_sqlite_not_supported(self):
-        self.assertRaises(changeset.exceptions.NotSupportedError,
-            self.table.c.data.alter,server_default=DefaultClause('tluafed'))
-        self.assertRaises(changeset.exceptions.NotSupportedError,
-            self.table.c.data.alter,nullable=True)
-        self.assertRaises(changeset.exceptions.NotSupportedError,
-            self.table.c.data.alter,type=String(21))
-        self.assertRaises(changeset.exceptions.NotSupportedError,
-            self.table.c.data.alter,name='atad')
-
-    @fixture.usedb(not_supported='sqlite')
+    @fixture.usedb()
     def test_rename(self):
         """Can rename a column"""
         def num_rows(col,content):
@@ -354,7 +339,7 @@ class TestColumnChange(fixture.DB):
         self.table.c.data   # Should not raise exception
         self.assertEquals(num_rows(self.table.c.data,content),1)
         
-    @fixture.usedb(not_supported='sqlite')
+    @fixture.usedb()
     def xtest_fk(self):
         """Can add/drop foreign key constraints to/from a column
         Not supported
@@ -371,7 +356,7 @@ class TestColumnChange(fixture.DB):
         self.refresh_table(self.table.name)
         self.assert_(self.table.c.data.foreign_key is None)
 
-    @fixture.usedb(not_supported='sqlite')
+    @fixture.usedb()
     def test_type(self):
         """Can change a column's type"""
         # Entire column definition given
@@ -394,7 +379,7 @@ class TestColumnChange(fixture.DB):
         self.refresh_table(self.table.name)
         self.assert_(isinstance(self.table.c.id.type,String))
 
-    @fixture.usedb(not_supported=('sqlite', 'mysql'))
+    @fixture.usedb(not_supported='mysql')
     def test_default(self):
         """Can change a column's server_default value (DefaultClauses only)
         Only DefaultClauses are changed here: others are managed by the 
@@ -427,7 +412,7 @@ class TestColumnChange(fixture.DB):
         self.assert_(row['data'] is None,row['data'])
         
 
-    @fixture.usedb(not_supported='sqlite')
+    @fixture.usedb()
     def test_null(self):
         """Can change a column's null constraint"""
         self.assertEquals(self.table.c.data.nullable,True)
@@ -443,11 +428,12 @@ class TestColumnChange(fixture.DB):
         self.refresh_table(self.table.name)
         self.assertEquals(self.table.c.data.nullable,True)
 
-    @fixture.usedb(not_supported='sqlite')
+    @fixture.usedb()
     def xtest_pk(self):
         """Can add/drop a column to/from its table's primary key
         Not supported
         """
+        self.engine.echo = True
         self.assertEquals(len(self.table.primary_key),1)
 
         # Entire column definition