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Displaying posts with tag: relation (reset)
MySQL – Alter table-change datatype of column with foreign key

Schema alteration is a big headache especially when it has already reached to production and things get worse when the relations are involved. Below is a short example for altering tables having foreign key constraints. SQL for tables used in example: create database temp;use temp; drop table if exists city; drop table if exists country; […]

A many to many relationship table – solving the exclude relation problem

A MySQL many to many relationship is a relationship that is multi-valued in both directions. Given that, how can you select rows that don’t have a specific relationship (the exclude relation problem)? I will start by defining the MySQL Many to Many relationship (Experts can skip to the next paragraph) What is A MySQL many […]

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