Master Save: Write a Tree of Rows Across Databases in One Call

Intro

0:00 One call writes a tree of rows : a customer in PostgreSQL, her order and its lines in MySQL. And when one row is wrong, nothing is written, in any database.

A tree of rows, the usual way

0:13 Saving a customer with her first order usually means three calls, one per table, in the right order, ids carried by hand from one call to the next, and a failure halfway that leaves half an order behind : no transaction spans two databases. With API Maker, one master save, the tree as it is, each row given the id of the row it belongs to, and a failure takes everything back, in every database.

0:40 In this video : a tree across two databases, one bad line, the tree saved, and read back.

A tree across two databases

0:47 API Testing, postgres, crm, customers, Master save. A new customer, Tara Kapoor. Under orders, her first order, in MySQL : the virtual field of video eleven. Under items, its two lines, in MySQL too. The second quantity is written in words.

All or nothing

1:10 Four hundred : the quantity of a line. The customer was already saved in PostgreSQL, the order and the first line in MySQL : all three were taken back. Nothing is left, in either database. Two, as a number. Two hundred and one : the customer, with her new id. Her order got that id as its customer_id, and each line the id of the order.

Read back

1:38 Query for get data : her e-mail, and deep, her orders, and their items. The customer from PostgreSQL, her order and its two lines from MySQL, in one answer.

How it is written

1:50 The writes follow the relations. A row a field points to is saved first, and its id is written in that field. The rows under a virtual field are saved after their parent, with its id. Every write is noted : when one fails, the others are taken back, the last one first.

Good to know

2:08 A row that carries its primary key is updated, not inserted : one tree can save and update. Every row goes through the schema of its own table : conversions and rules. From code, g.sys.db.masterSave does the same. And if a take-back itself fails, the answer says so, next to the error that started it.

Built on standards

2:30 One call for a tree of rows. All or nothing, across databases. So a client, written by you or by an AI assistant, never leaves half an order behind.

Recap

2:42 To sum up. One master save, a tree across databases. Each row given the id it needs. One bad row, nothing written anywhere. The tree read back with deep. Next : deep populate, in depth. API Maker. Build faster, spend smarter, deliver better.