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

1 files changed, 37 insertions, 13 deletions

diff --git a/migrate/changeset/databases/sqlite.py b/migrate/changeset/databases/sqlite.py
index a0b85d2..0f560c1 100644
--- a/migrate/changeset/databases/sqlite.py
+++ b/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 "