- The primary key is the criteria of the table. In other words, criteria table key is primary key.
- Example1 : When join parent table with child table 1, primary key of parent table is a criteria key.
| Parent Table | |
| Primary Key | Foreign Key |
Join : Primary Key<->Foreign Key
| Child Table 1 | |
| Primary Key | Foreign Key |
- Example2 : When join child table 1 with child table 2, primary key of child table1 is a criteria key.
Join : Primary Key<->Foreign Key
| Child Table 2 | |
| Primary Key | Foreign Key |
'DataBase > MYSQL' 카테고리의 다른 글
| SQL, Docker-compose, Python module (0) | 2022.02.03 |
|---|---|
| Common SQL queries in Pandas (0) | 2022.01.24 |
| SQL error:may be the input source is a directory or a block device (0) | 2022.01.24 |
| How to run mySQL through docker-compose. (0) | 2022.01.13 |
| MYSQL Query (0) | 2022.01.13 |