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Problems and Solutions

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Error "Column type for TableName#ColumnName is not defined and cannot be guessed"​

ColumnTypeUndefinedError: Column type for TableName#ColumnName is not defined and cannot be guessed. Make sure you have turned on an "emitDecoratorMetadata": true option in tsconfig.json. Also make sure you have imported "reflect-metadata" on top of the main entry file in your application (before any entity imported).If you are using JavaScript instead of TypeScript you must explicitly provide a column type.

The problem may occur even if the emitDecoratorMetadata parameter is enabled, the reflect-metadata package is installed and imported, and the fields have a standard type explicitly specified.

This is because TypeORM cannot determine the type.

To avoid such problems, it is better to always explicitly specify the type for columns, rather than relying on type guessing magic.

@Entity({ name: 'Users' })
export class User {
- @PrimaryColumn({ name: 'Id' })
+ @PrimaryColumn({ name: 'Id', type: 'text' })
  public id: string

- @Column({ name: 'Name', nullable: false })
+ @Column({ name: 'Name', type: 'text', nullable: false })
  public name: string
}