Databases

In TypeORM, you can select a single or multiple random rows by adding orderBy(‘RANDOM()’) to your query builder. Let’s see a couple of examples below for more clarity. Let’s say we have a User entity like…

In TypeORM, you can select rows in a table based on the relation columns (in the related table) by using a query builder like this: The code snippet above retrieves all posts that were created by…

When working with a database, the cascade delete feature ensures that deleting a parent record will also remove the child records. For instance, we have a table that stores information about users and another table that…

In TypeORM, you can simply connect to multiple databases simultaneously just by creating multiple data sources. The Steps 1. Setup your data sources: 2. The next step is to initialize the connections (usually placed in the…

In TypeORM, you can execute raw SQL queries by calling the query() method (you can access this method via your data source or the entity manager). You can do everything from CRUD data (create, read, update,…

In TypeORM, you can order your results by multiple columns. The 2 examples below show you how to do that. The first example uses the find() method whilst the second one uses a query builder. In…

This article is about using subqueries with query builders in TypeORM. Let’s say we have an entity named Product: The code snippet below finds products with a higher than average price by using a subquery (that…

When communicating with databases through TypeORM, you can get raw SQL queries produced by query builders by using the getQuery() or getSql() methods (you can use them synchronously without the await keyword). Example: Output: If you…

This succinct tutorial shows you how to use column aliases to assign temporary names to columns when selecting data with TypeORM. The point here is the AS keyword. Let’s study a couple of examples for more…

In real life, it’s possible that a column contains many duplicate values. However, there might be occasions when you only want to get different (unique) values. If you’ve worked with MySQL or PostgreSQL, you are very…

When using TypeORM to interact with databases, there might be occasions when you want to take records and sort them based on a relational field. There are 2 solutions for this: using find options and using…

When communicating with the database through TypeORM, there will be many cases where you need to count records in a one-to-many relationship, such as: You want to list the users and the number of photos belonging…