Room Database Migration with Indexed Entity

Question

I have 'ImagePendingDBStore' entity, I have added 4 more columns in this entity (see comment in code below). In this, one column is indexed 'referenceId'

@Entity(tableName = "ImagePendingDBStore",indices = {@Index(value = "referenceId")})
public class ImagePendingDBStore {

 @PrimaryKey(autoGenerate = true)
 @NonNull
 private int ImageId;
 private String referenceId;
 private Date createdAt;
 private Date updatedAt;
 private String imageAbsolutePath;
 private int synced = 0;
 private String customerFirstName;
 private String customerMiddleName;
 private String customerLastName;
 private String dasId;
 private String documentName;
 private String imageIdRandom;
 private int imageResolution;

 //new columns
 private String dealerId;
 private String lat;
 private String lng;
 private Date imageCaptureDate;
}

My migration logic in database class is as below:

public static final Migration MIGRATION_1_2 = new Migration(1, 2) {
    @Override
    public void migrate(SupportSQLiteDatabase database) {
        database.execSQL("ALTER TABLE ImagePendingDBStore ADD COLUMN dealerId TEXT");
        database.execSQL("ALTER TABLE ImagePendingDBStore ADD COLUMN lat TEXT");
        database.execSQL("ALTER TABLE ImagePendingDBStore ADD COLUMN lng TEXT");
        database.execSQL("ALTER TABLE ImagePendingDBStore ADD COLUMN imageCaptureDate DATE");
        database.execSQL("CREATE  INDEX index_ImagePendingDBStore_referenceId ON ImagePendingDBStore (referenceId)");
    }
};

Below is the error I am facing:

Caused by: android.database.sqlite.SQLiteException: index index_ImagePendingDBStore_referenceId already exists (code 1): , while compiling: CREATE INDEX index_ImagePendingDBStore_referenceId ON ImagePendingDBStore (referenceId)
    #################################################################
    Error Code : 1 (SQLITE_ERROR)
    Caused By : SQL(query) error or missing database.
        (index index_ImagePendingDBStore_referenceId already exists (code 1): , while compiling: CREATE INDEX index_ImagePendingDBStore_referenceId ON ImagePendingDBStore (referenceId))
    #################################################################

Answer 1

As the message says index_ImagePendingDBStore_referenceId already exists.

You only need the 4 ALTER statements as the index exists i.e. you have not added it. As it already exists then adding the 4 columns doesn't require the index to be changed.

You could remove the line :-

database.execSQL("CREATE  INDEX index_ImagePendingDBStore_referenceId ON ImagePendingDBStore (referenceId)");