+
−def migrate_varchar_to_nvarchar():
+
−    dbdriver  = config.sources()['system']['db-driver']
+
−    if dbdriver != "sqlserver2005":
+
−        return
+
−
+
−    introspection_sql = """\
+
−SELECT table_schema, table_name, column_name, is_nullable, character_maximum_length
+
−FROM information_schema.columns
+
−WHERE data_type = 'VARCHAR' and table_name <> 'SYSDIAGRAMS'
+
−"""
+
−    has_index_sql = """\
+
−SELECT i.name AS index_name,
+
−       i.type_desc,
+
−       i.is_unique,
+
−       i.is_unique_constraint
+
−FROM sys.indexes AS i, sys.index_columns as j, sys.columns as k
+
−WHERE is_hypothetical = 0 AND i.index_id <> 0
+
−AND i.object_id = j.object_id
+
−AND i.index_id = j.index_id
+
−AND i.object_id = OBJECT_ID('%(table)s')
+
−AND k.name = '%(col)s'
+
−AND k.object_id=i.object_id
+
−AND j.column_id = k.column_id;"""
+
−
+
−    generated_statements = []
+
−    for schema, table, column, is_nullable, length in sql(introspection_sql, ask_confirm=False):
+
−        qualified_table = '[%s].[%s]' % (schema, table)
+
−        rset = sql(has_index_sql % {'table': qualified_table, 'col':column},
+
−                   ask_confirm = False)
+
−        drops = []
+
−        creates = []
+
−        for idx_name, idx_type, idx_unique, is_unique_constraint in rset:
+
−            if is_unique_constraint:
+
−                drops.append('ALTER TABLE %s DROP CONSTRAINT %s' % (qualified_table, idx_name))
+
−                creates.append('ALTER TABLE %s ADD CONSTRAINT %s UNIQUE (%s)' % (qualified_table, idx_name, column))
+
−            else:
+
−                drops.append('DROP INDEX %s ON %s' % (idx_name, qualified_table))
+
−                if idx_unique:
+
−                    unique = 'UNIQUE'
+
−                else:
+
−                    unique = ''
+
−                creates.append('CREATE %s %s INDEX %s ON %s(%s)' % (unique, idx_type, idx_name, qualified_table, column))
+
−
+
−        if length == -1:
+
−            length = 'max'
+
−        if is_nullable == 'YES':
+
−            not_null = 'NULL'
+
−        else:
+
−            not_null = 'NOT NULL'
+
−        alter_sql = 'ALTER TABLE %s ALTER COLUMN %s NVARCHAR(%s) %s' % (qualified_table, column, length, not_null)
+
−        generated_statements+= drops + [alter_sql] + creates
+
−
+
−
+
−    for statement in generated_statements:
+
−        print statement
+
−        sql(statement, ask_confirm=False)
+
−    commit()
+
−
+
−migrate_varchar_to_nvarchar()