Function discoverExistingRecordsWithColumns

discoverExistingRecordsWithColumns(
    d1: SQLDatabase,
    tableName: string,
    primaryKeyColumn?: string,
): Promise<{ [key: string]: any }[]>
Discovers existing records with additional columns for multi-key mapping support. Scans a table to find primary keys along with username, email, and name columns when they exist, allowing these additional columns to be used as lookup keys.
Parameters
- d1: SQLDatabase
  The D1 database instance to scan
- tableName: string
  Name of the table to discover records from
- primaryKeyColumn: string = 'id'
  Name of the primary key column (defaults to 'id')
Returns Promise<{ [key: string]: any }[]>
Promise resolving to array of record data with available columns
Throws
If table doesn't exist or database query fails
Example
```
// Discover all user records with available lookup columns
const records = await discoverExistingRecordsWithColumns(env.DB_EXISTING, 'users');
console.log(`Found ${records.length} user records`);
records.forEach(record => {
  console.log(`ID: ${record.id}, Email: ${record.email || 'N/A'}`);
});
```
Since
1.0.4
- Defined in src/migrations.ts:387