schema-evolution: re-applied schema evolution changes from:

http://kered.org/blog/wp-content/uploads/2007/07/django_schema_evolution-svn20070719patch.txt



git-svn-id: http://code.djangoproject.com/svn/django/branches/schema-evolution@5735 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 82 insertions, 0 deletions

diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index a0b1341b53..0bae2de216 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -214,6 +214,51 @@ def _sqlite_regexp(re_pattern, re_string):
     except:
         return False
 
+def get_change_column_name_sql( table_name, indexes, old_col_name, new_col_name, col_def ):
+    # sqlite doesn't support column renames, so we fake it
+    # TODO: only supports a single primary key so far
+    pk_name = None
+    for key in indexes.keys():
+        if indexes[key]['primary_key']: pk_name = key
+    output = []
+    output.append( 'ALTER TABLE '+ quote_name(table_name) +' ADD COLUMN '+ quote_name(new_col_name) +' '+ col_def + ';' )
+    output.append( 'UPDATE '+ quote_name(table_name) +' SET '+ new_col_name +' = '+ old_col_name +' WHERE '+ pk_name +'=(select '+ pk_name +' from '+ table_name +');' )
+    output.append( '-- FYI: sqlite does not support deleting columns, so  '+ quote_name(old_col_name) +' remains as cruft' )
+    # use the following when sqlite gets drop support
+    #output.append( 'ALTER TABLE '+ quote_name(table_name) +' DROP COLUMN '+ quote_name(old_col_name) )
+    return '\n'.join(output)
+
+def get_change_column_def_sql( table_name, col_name, col_def ):
+    # sqlite doesn't support column modifications, so we fake it
+    output = []
+    # TODO: fake via renaming the table, building a new one and deleting the old
+    output.append('-- sqlite does not support column modifications '+ quote_name(table_name) +'.'+ quote_name(col_name) +' to '+ col_def)
+    return '\n'.join(output)
+    
+def get_add_column_sql( table_name, col_name, col_type, null, unique, primary_key  ):
+    output = []
+    field_output = []
+    field_output.append('ALTER TABLE')
+    field_output.append(quote_name(table_name))
+    field_output.append('ADD COLUMN')
+    field_output.append(quote_name(col_name))
+    field_output.append(col_type)
+    field_output.append(('%sNULL' % (not null and 'NOT ' or '')))
+    if unique:
+        field_output.append(('UNIQUE'))
+    if primary_key:
+        field_output.append(('PRIMARY KEY'))
+    output.append(' '.join(field_output) + ';')
+    return '\n'.join(output)
+
+def get_drop_column_sql( table_name, col_name ):
+    output = []
+    output.append( '-- FYI: sqlite does not support deleting columns, so  '+ quote_name(old_col_name) +' remains as cruft' )
+    # use the following when sqlite gets drop support
+    # output.append( '-- ALTER TABLE '+ quote_name(table_name) +' DROP COLUMN '+ quote_name(col_name) )
+    return '\n'.join(output)
+    
+
 # SQLite requires LIKE statements to include an ESCAPE clause if the value
 # being escaped has a percent or underscore in it.
 # See http://www.sqlite.org/lang_expr.html for an explanation.
diff --git a/django/db/backends/sqlite3/introspection.py b/django/db/backends/sqlite3/introspection.py
index 4e22c5ea42..ce033757c9 100644
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@@ -43,6 +43,43 @@ def get_indexes(cursor, table_name):
         indexes[name]['unique'] = True
     return indexes
 
+def get_columns(cursor, table_name):
+    try:
+        cursor.execute("PRAGMA table_info(%s)" % quote_name(table_name))
+        return [row[1] for row in cursor.fetchall()]
+    except:
+        return []
+	
+def get_known_column_flags( cursor, table_name, column_name ):
+    cursor.execute("PRAGMA table_info(%s)" % quote_name(table_name))
+    dict = {}
+    for row in cursor.fetchall():
+        if row[1] == column_name:
+
+            # maxlength check goes here
+            if row[2][0:7]=='varchar':
+                dict['maxlength'] = row[2][8:len(row[2])-1]
+            
+            # default flag check goes here
+            #if row[2]=='YES': dict['allow_null'] = True
+            #else: dict['allow_null'] = False
+            
+            # primary/foreign/unique key flag check goes here
+            #if row[3]=='PRI': dict['primary_key'] = True
+            #else: dict['primary_key'] = False
+            #if row[3]=='FOR': dict['foreign_key'] = True
+            #else: dict['foreign_key'] = False
+            #if row[3]=='UNI': dict['unique'] = True
+            #else: dict['unique'] = False
+            
+            # default value check goes here
+            # if row[4]=='NULL': dict['default'] = None
+            # else: dict['default'] = row[4]
+            #dict['default'] = row[4]
+            
+    print table_name, column_name, dict
+    return dict
+    
 def _table_info(cursor, name):
     cursor.execute('PRAGMA table_info(%s)' % quote_name(name))
     # cid, name, type, notnull, dflt_value, pk