Relationship between easy-to-use order data tables

The foreign key is not used in the easy-to-use database, but the table has a close relationship with the table. CodeThen, the following relationships are identified:
The query of orders is very disgusting during the migration, so you need to study it carefully. Source codeIt includes complex queries, and works completely by concatenating strings. Note that the foreign key relationship of each table needs to be maintained in the inverted data, because the easy-to-use foreign key does not exist, but it is just the definition of the field (it can be seen that it is quite disgusting ). Tables related to the order user. These tables are indispensable when they are inverted. The first table is the customer table, after reversing the table, you can inverted the contact table (which contains the association ID of the customer table), and then inverted the user table (which contains the contact information ), last inverted order table (with user and customer Associations)