How to dynamically get column names from TypeORM?

user_4180797 0
Viewed 3463

I have tried

let modelClass = (await import('@models/' + modelName + '.ts'))[modelName];
let keys = Object.keys(modelClass);//no column names included, only custom helper vars i.e. NoteColumnVarcharLength
let keys = Object.keys(new modelClass());//nothing at all in this model

Is there a helper function in the library to automatically get them all?

typeorm javascript
2 Answers

As proposed in the issue on repository of that library (link) can be solved by using

connection.getMetadata("User").columns
user_111960380

The accepted answer looks incomplete, and many questions appeared in my head when I tried to apply the answer. So I write my own to cover the question well.

To get column names, we must first retrieve EntityMetadata. We can retrieve EntityMetadata from Connection, which we can get in any comfortable way.

import { getConnection, getManager } from 'typeorm';

const connection1 = getConnection();
const connection2 = getManager().connection;

Next, we need to retrieve entity metadata.

We can do it via

const metadata = connection.getMetadata(modelClass);

Inside entity medatata you can use several options to find a column. If you need to look for all columns, you need to use columns. If you are going to look only over user-defined columns, you can use ownColumns.

These properties contains arrays with ColumnMetadata.

If you just need a list of user-defined columns, you can just return a mapped values of propertyName.

const columns = metadata.columns.map((column) => column.propertyName);

In my case, I needed to find database column name by a property name.

I used a find() for my case.

const column = metadata.ownColumns.find((column) => column.propertyName === propertyName);

If I need to find several column I would create a map between propertyName and databaseName;

const columnMap = Object.fromEntries(
  metadata.ownColumns((column) => ([column.propertyName, column.databaseName]))
);
user_66255480
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