Relations Across Databases and the ER Diagram

Intro

0:00 A few lines in a schema link two tables, whatever their engines : deep populate, find and join, master save and the ER diagram follow them. In this video, the shipments of the warehouse meet the orders of the shop.

Relations, the usual way

0:13 Data spread over several databases usually means joins written in the application, call by call, foreign keys that stop at the edge of one database, and a diagram drawn by hand, out of date the week after. With API Maker, a relation is a few keys in a schema, between any two engines, the server checks every name when you save, and the ER diagram is drawn from the schemas.

0:39 In this video : a relation typed in a schema, two typos caught, the relation at work, the ER diagram of six engines, and one table and its links.

A relation, typed

0:50 Instance API, sqlserver, warehouse, dbo.shipments, its schema. A shipment of SQL Server ships an order of MySQL. Under order_id : the instance mysql, the database, the table orders and its column id. With two typos, the way they happen. Update : refused. order_id names a column but no table : tabel is not a key. table. Update : saved, with a warning, there is no schema for mysql, sale, orders.

1:25 The database name is wrong. sales. Update and Close : saved, nothing to warn about.

What a relation is

1:33 A relation is a few keys on a column : the instance and the database when the table lives elsewhere, then the table and its column. Any column : an id, a sku, a coupon code. Inside one SQL database, the foreign keys became relations when the schema was written.

The relation at work

1:53 API Testing, sqlserver, warehouse, dbo.shipments, Get all. Shipment one, and deep : order_id. The shipment of SQL Server, and inside it, its order of MySQL. One call, two engines.

The ER diagram

2:13 Database, ER Diagram. The six instances : MongoDB, MySQL, MariaDB, PostgreSQL, SQL Server and Oracle. Apply Selection : every table of the account, and every relation, across the engines. More room, Auto-Arrange, and the legend : primary keys, foreign keys, required fields. Search : shipments. The table, its relations lit : warehouse_id to the warehouses, in the same database, and order_id. Fit again : the line of order_id reaches the orders, in MySQL.

Good to know

2:52 Master save, deep populate and find and join follow these relations : videos nine, ten and twelve. Virtual fields describe the other side, one to many : video eleven. The diagram exports as PNG or SVG. And a relation is part of the schema : it goes to Git with it.

Built on standards

3:12 One place for the links between tables : the schema, read by every API and by the diagram. Every name is checked when you save : a key that does not exist is refused, a table that is not there is reported. So a relation written by an AI assistant gets the same checks.

Recap

3:31 To sum up. A relation, a few keys in a schema, across engines. Names checked when saved. Followed by deep populate and the other APIs. The ER diagram of the whole account. Next : the generated APIs, a tour. API Maker. Build faster, spend smarter, deliver better.