SQLite: Foreign KEY table constraint
Link: https://www.meetgor.com/sqlog/sqlite-foreign-key-table-constraint
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Source: techstructive-weekly-60
Posts for: #Sql
SQLite: Many to Many Relations
SQLite: Many to Many Relations
Link: https://www.meetgor.com/sqlog/sqlite-many-to-many-relations
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Source: techstructive-weekly-60
SQLite: One to Many Relation with Foreign Key
SQLite: One to Many Relation with Foreign Key
Link: https://www.meetgor.com/sqlog/sqlite-one-to-many-foreign-key
Context
Source: techstructive-weekly-60
SQLite: One to One Relations
SQLite: One to One Relations
Link: https://www.meetgor.com/sqlog/sqlite-one-to-one-relations
Context
Source: techstructive-weekly-60
SQLite: PRIMARY KEY column constraint
SQLite: PRIMARY KEY column constraint
Link: https://www.meetgor.com/sqlog/sqlite-primary-key-column-constraint
Context
Source: techstructive-weekly-60
SQLite: PRIMARY KEY table constraint
SQLite: PRIMARY KEY table constraint
Link: https://www.meetgor.com/sqlog/sqlite-primary-key-table-constraint
Context
Source: techstructive-weekly-60
SQLite: Self Join Relations
SQLite: Self Join Relations
Link: https://www.meetgor.com/sqlog/sqlite-self-join-relations
Context
Source: techstructive-weekly-60
Techstructive Weekly #60
Weekly #60
Another great week, consistently learning SQL, developing another streak for solving problems on FreeCodeCamp with Javascript and Python, reading instead of doomscrolling.
SQLite SQL: Many to Many Relations
Many to Many Relations
We have seen one-to-many relationship and also the self-join relationship.
Let’s extend it with many-to-many relationship. Here one row can refer to many other rows, but that other row can also be referred by multiple rows.
That was confusing, let’s take the simple example of users and posts as usual.
- In
One-To-Manyrelation, one post can only be written by one user. However, one user can author multiple posts. - In
Many-To-Manyrelation, one user can author multiple posts and one post can be written by multiple users.
That is the distinction, it is not about the relation, it is more about the design that your system needs.
SQLite SQL: Self Join Relations
Self Join Relations
In the last post, we had defined a one-to-many relation between the users table and the posts table.
Now, let’s create a single table where we can define a one-to-many relationship. Yes, within a single table we can reference the primary key and it can act like a link. Since it isn’t really about the table, it’s more about the row relation form each other, we an connect any rows.