TypeORM throws a ColumnTypeUndefinedError when encountering a situation where

Question

TypeORM throws a ColumnTypeUndefinedError when encountering a situation where

Upon launching my project, I encountered the following error:

ColumnTypeUndefinedError: Column type for Order#author is not defined and cannot be guessed. To resolve this issue, ensure that you have enabled the "emitDecoratorMetadata": true option in tsconfig.json. Additionally, make sure to import "reflect-metadata" at the top of your main entry file in the application (before any entity imports). If you are using JavaScript instead of TypeScript, you must explicitly specify a column type.

My column appears as shown below:

    @Column({
        nullable: true
    })
    author: User;

javascript mysql sql typescript typeorm

Answer 1

Answer №1

Check your tsconfig configuration file and make sure to uncomment the line

"emitDecoratorMetadata": true,

. Next, navigate to your main application file (e.g. app.ts, index.ts, server.ts) and add an import statement for reflect-metadata as shown below:

import "reflect-metadata";

Answer 2

Check your tsconfig configuration file and make sure to uncomment the line

"emitDecoratorMetadata": true,

. Next, navigate to your main application file (e.g. app.ts, index.ts, server.ts) and add an import statement for reflect-metadata as shown below:

import "reflect-metadata";

Answer 3

Answer №2

To specify the type of data in your column, use the following syntax:

@Column({
  type: 'varchar',
  nullable: true
})
author: User;

Answer 4

To specify the type of data in your column, use the following syntax:

@Column({
  type: 'varchar',
  nullable: true
})
author: User;

Answer 5

Answer №3

The reason for this issue is that the database is not aware of the User type.

To resolve this, simply change User to string, as the database recognizes string:

@Column({
        nullable: true
    })
    author: string;

If you prefer to use User instead of string, utilize @ManyToOne in place of @Column. This establishes a foreign key relationship with the User table, and by adding eager: true, the User entity will be automatically loaded alongside the base entity when executing any of TypeOrm's find* methods:

@ManyToOne(() => User, { eager: true })
author: User;

Answer 6

The reason for this issue is that the database is not aware of the User type.

To resolve this, simply change User to string, as the database recognizes string:

@Column({
        nullable: true
    })
    author: string;

If you prefer to use User instead of string, utilize @ManyToOne in place of @Column. This establishes a foreign key relationship with the User table, and by adding eager: true, the User entity will be automatically loaded alongside the base entity when executing any of TypeOrm's find* methods:

@ManyToOne(() => User, { eager: true })
author: User;

Answer 7

Answer №4

your tsconfig.json file is not properly configured, resulting in the error you're encountering. To resolve this issue, include the following code in your file:

{
    "emitDecoratorMetadata": true,
    "lib": ["es5", "es6", "dom"],  
    "moduleResolution": "node",
    "target": "es5", 
}

Next, execute the command:

npm run tsc

Once you have made the necessary changes to your tsconfig file, proceed with recompilation.

Answer 8

your tsconfig.json file is not properly configured, resulting in the error you're encountering. To resolve this issue, include the following code in your file:

{
    "emitDecoratorMetadata": true,
    "lib": ["es5", "es6", "dom"],  
    "moduleResolution": "node",
    "target": "es5", 
}

Next, execute the command:

npm run tsc

Once you have made the necessary changes to your tsconfig file, proceed with recompilation.

TypeORM throws a ColumnTypeUndefinedError when encountering a situation where

Answer №1

Answer №2

Answer №3

Answer №4

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