Question 1

What is an Entity in TypeORM?

Accepted Answer

An Entity in TypeORM is a TypeScript class decorated with @Entity() that represents a database table. Each instance of the Entity corresponds to a row in the table. Class properties are automatically mapped to table columns using decorators like @Column().

Question 2

Which decorator to use to mark a property as a column in TypeORM?

Accepted Answer

The @Column() decorator transforms a class property into a database column. TypeORM automatically infers the SQL type from the TypeScript type, but it can be explicitly specified with @Column('varchar', { length: 255 }). This decorator is essential for all columns except the primary key.

Question 3

What is the difference between @PrimaryColumn() and @PrimaryGeneratedColumn()?

Accepted Answer

@PrimaryGeneratedColumn() creates a primary key auto-incremented by the database, ideal for numeric identifiers. @PrimaryColumn() defines a primary key whose value must be provided manually, useful for UUID identifiers or composite keys. For most cases, using @PrimaryGeneratedColumn() is simpler and safer.

Database with TypeORM

What is an Entity in TypeORM?

Câu trả lời

Which decorator to use to mark a property as a column in TypeORM?

Câu trả lời

What is the difference between @PrimaryColumn() and @PrimaryGeneratedColumn()?

Câu trả lời

How to inject a TypeORM repository into a NestJS service?

Which decorator to use to define a nullable column in TypeORM?

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