[#63] New DataSource Module

* New submodule MySQL
* Unsuseful methods deleted
* Methods to create table and field names in the unified DataSource class

DataSource/MySQL/MySQL.py

@@ -0,0 +1,87 @@
+# -*- coding: utf8 -*-
+
+
+import EditorialModel
+
+## @brief Manages the accesses to a MySQL datasource
+class MySQL(object):
+
+    _relations_table_name = 'relation'
+    _relations_field_nature = 'nature'
+    _field_lodel_id = 'lodel_id'
+    _class_table_prefix = 'class_'
+    _objects_table_name = 'object'
+    _connections = {
+        'default':{
+            'module': pymysql,
+            'host': '127.0.0.1',
+            'user': 'lodel',
+            'passwd': 'bruno',
+            'db': 'lodel2'
+        }
+    }
+
+    @classmethod
+    ## @brief gets the table name from class name
+    # @param class_name str
+    # @return str
+    def get_table_name_from_class(cls, class_name):
+        return "%s%s" % (cls._class_table_prefix, class_name)
+
+    @classmethod
+    ## @brief gets the table name given a class, a type and a field names
+    # @param class_name str
+    # @param type_name str
+    # @param field_name str
+    # @return str
+    def get_r2t2table_name(cls, class_name, type_name, field_name):
+        return "%s_%s_%s" % (class_name, type_name, field_name)
+
+    @classmethod
+    ## @brief gets the fk name between two tables
+    # @param src_table_name str
+    # @param dst_table_name str
+    # @return str
+    def _fk_name(cls, src_table_name, dst_table_name):
+        return "fk_%s_%s" % (src_table_name, dst_table_name)
+
+    @classmethod
+    ## @brief Identifier escaping
+    # @param idname str : An SQL identifier
+    def escape_idname(cls, idname):
+        if '`' in idname:
+            raise ValueError("Invalid name : '%s'" % idname)
+        return '`%s`' % idname
+
+
+    @classmethod
+    ## @brief Given a fieldtype, returns a MySQL type specifier
+    # @param emfieldType EmFieldType : A fieldtype
+    # @return str
+    def get_type_spec_from_fieldtype(cls, emfieldtype):
+
+        ftype = emfieldtype.ftype
+
+        if ftype == 'char' or ftype == 'str':
+            res = "VARCHAR(%d)" % emfieldtype.max_length
+        elif ftype == 'text':
+            res = 'TEXT'
+        elif ftype == 'datetime':
+            res = "DATETIME"
+            # client side workaround for only one column with CURRENT_TIMESTAMP : giving NULL to timestamp that don't allows NULL
+            # cf. https://dev.mysql.com/doc/refman/5.0/en/timestamp-initialization.html#idm139961275230400
+            # The solution for the migration handler is to create triggers :
+            # CREATE TRIGGER trigger_name BEFORE INSERT ON `my_super_table`
+            # FOR EACH ROW SET NEW.my_date_column = NOW();
+            # and
+            # CREATE TRIGGER trigger_name BEFORE UPDATE ON
+        elif ftype == 'bool':
+            res = "BOOL"
+        elif ftype == 'int':
+            res = "INT"
+        elif ftype == 'rel2type':
+            res = "INT"
+        else:
+            raise ValueError("Unsupported fieldtype ftype : %s" % ftype)
+
+        return res