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android – Room Database Migration doesnt properly handle ALTER TABLE migration

Posted by: admin April 23, 2020 Leave a comment

Questions:

Java.lang.IllegalStateException

Migration didn’t properly handle
user(therealandroid.github.com.roomcore.java.User).

Expected:

TableInfo{name=’user’, columns={name=Column{name=’name’, type=’TEXT’,
notNull=false, primaryKeyPosition=0}, age=Column{name=’age’,
type=’INTEGER’, notNull=true, primaryKeyPosition=0},
id=Column{name=’id’, type=’INTEGER’, notNull=true,
primaryKeyPosition=1}}, foreignKeys=[]} Found:

Found

TableInfo{ name=’user’, columns={name=Column{name=’name’, type=’TEXT’,
notNull=false, primaryKeyPosition=0}, id=Column{name=’id’,
type=’INTEGER’, notNull=true, primaryKeyPosition=1},
age=Column{name=’age’, type=’INTEGER’, notNull=false,
primaryKeyPosition=0}}, foreignKeys=[]}

I’m trying to perform a simple migration, I have a class called Userand it have two columns ID (primary key) and NAME TEXT and then I populate database with two users data, then I add the column AGE in the object User and in the Migration constant I add an alter table to add this new column and lastly I replace version of the database 1 to 2.

Here is the code

User.class

@Entity(tableName = "user")
  public class User {

  @PrimaryKey
  private int id;

  @ColumnInfo(name = "name")
  private String name;

  @ColumnInfo(name = "age")
  private int age;


  public int getId() {
      return id;
  }

  public void setId(int id) {
      this.id = id;
  }

  public String getName() {
      return name;
  }

  public void setName(String name) {
      this.name = name;
  }

  public int getAge() {
      return age;
  }

  public void setAge(int age) {
      this.age = age;
  }
}

Database class

@Database(entities = {User.class}, version = 2)
public abstract class RoomDatabaseImpl extends RoomDatabase {
    abstract UserDao userDao();
}

Migration code

public static Migration MIGRATION_1_2 = new Migration(1, 2) {
    @Override
    public void migrate(SupportSQLiteDatabase database) {
        database.execSQL("ALTER TABLE 'user' ADD COLUMN 'age' INTEGER");
    }
 };

and it call

Room.databaseBuilder(context, RoomDatabaseImpl.class, "Sample.db")
            .addMigrations(MIGRATION_1_2)
            .allowMainThreadQueries()
            .build();

Before change the object adding AGE and performing the migration I add two register and it works.

After performing the migration, I just tried to add a new User as bellow:

  User user = new User();
  user.setName("JoooJ");
  user.setId(3);
  user.setAge(18);

  List<User> userList = new ArrayList<>();
  userList.add(user);
  App.database(this).userDao().insertAll(userList);  // The crash happens here

Other informations:

Android Studio 3 and I didn’t tested in the actual.

Dependencies:

compile "android.arch.persistence.room:runtime:1.0.0-alpha9-1"
annotationProcessor "android.arch.persistence.room:compiler:1.0.0-alpha9-1"

compile "android.arch.persistence.room:rxjava2:1.0.0-alpha9-1"
gradle 2.3.3

Can someone help me please, I realy don’t know what im doing wrong or if it is a bug.

How to&Answers:

The error message is hard to parse, but there’s a difference:

TableInfo{name=’user’, columns={name=Column{name=’name’, type=’TEXT’, notNull=false, primaryKeyPosition=0}, age=Column{name=’age’, type=’INTEGER’, notNull=true, primaryKeyPosition=0}, id=Column{name=’id’, type=’INTEGER’, notNull=true, primaryKeyPosition=1}}, foreignKeys=[]} Found:

Found

TableInfo{ name=’user’, columns={name=Column{name=’name’, type=’TEXT’, notNull=false, primaryKeyPosition=0}, id=Column{name=’id’, type=’INTEGER’, notNull=true, primaryKeyPosition=1}, age=Column{name=’age’, type=’INTEGER’, notNull=false, primaryKeyPosition=0}}, foreignKeys=[]}

Age is nullable but Room expected it to be not null.

Change your migration to:

database.execSQL("ALTER TABLE 'user' ADD COLUMN 'age' INTEGER NOT NULL");

Since this exception explanation is VERY difficult to parse, I have created a small script that does the diff for you.

Example:

mig "java.lang.IllegalStateException: Migration failed. expected:TableInfo{name='user', columns={name=Column{name='name', type='TEXT', notNull=false, primaryKeyPosition=0}, age=Column{name='age', type='INTEGER', notNull=true, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', notNull=true, primaryKeyPosition=1}}, foreignKeys=[]} , found:TableInfo{name='user', columns={name=Column{name='name', type='TEXT', notNull=false, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', notNull=true, primaryKeyPosition=1}, age=Column{name='age', type='INTEGER', notNull=false, primaryKeyPosition=0}}, foreignKeys=[]}"

Result:

expected/found diff

Answer:

I too wrote a small JS script which you can find https://hrankit.github.io/RoomSQLiteDifferenceFinder/

The process is pretty Simple.

  1. Input the Expected error log in Expected column which is the Left One.

  2. Input the Found error log in Found column which is the Right One.

  3. Press Go. button. The error logs get converted to JSON.

  4. Press Compare button and Voila, you have the difference you need.

This plugin finds out the difference in the two Expected and Found dump from the Android Studio Logcat.

Checkout the image of comparison here

Answer:

None of the answers are correct in any of the links. After much experiments, found a way for it. The ALTER query needs to be written in the following way to make it work:

database.execSQL("ALTER TABLE 'user' ADD COLUMN 'age' INTEGER NOT NULL DEFAULT 0")

However, the Integer DEFAULT value can be anything.

If you want to add String type column, add in the following manner:

database.execSQL("ALTER TABLE 'user' ADD COLUMN 'address' TEXT")

This works like a charm.

Answer:

I faced this issue today, I just changed int fields to Integer in Entities. As int cannot be null but Integer objects could be null.

Answer:

If you are getting notNull differences, you can simply mark your class field with @NonNull annotation, or change your sql with ALTER TABLE. But if you are getting column type differences, such as expected: TYPE=TEXT, then found TYPE=” (COLLATE NOCASE), or expected INTEGER, found INT, then the only solution is to drop and recreate your table. Sqlite does not allow changing column types.

Use INTEGER in Sqlite instead of INT and mark your Java entity with @ColumnInfo(collate = NOCASE) (if you use NOCASE in Sqlite).

Take a look at the json file under app\schemas to get the sql for the expected queries.

static final Migration MIGRATION_2_3= new Migration(2, 3) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {

            database.execSQL("DROP TABLE IF EXISTS table_tmp");

            database.execSQL("CREATE TABLE IF NOT EXISTS `table_tmp` ...");

            database.execSQL("insert into table_tmp (`id`, `name` , ...");

            database.execSQL("DROP INDEX IF EXISTS `index_table_name`");

            database.execSQL("CREATE INDEX IF NOT EXISTS `index_table_name` ON `table_tmp` (`name`)");

            database.execSQL("DROP TABLE IF EXISTS table");

            database.execSQL("alter table table_tmp rename to table");

        }
    };

Answer:

I have faced notNull differences in kotlin and found exception like below

Expected:
TableInfo{name='enDic', columns={definition=Column{name='definition', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, _id=Column{name='_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, favourite=Column{name='favourite', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, word=Column{name='word', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, usage=Column{name='usage', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}
Found:
TableInfo{name='enDic', columns={usage=Column{name='usage', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=0, defaultValue='null'}, definition=Column{name='definition', type='text', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, _id=Column{name='_id', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=1, defaultValue='null'}, favourite=Column{name='favourite', type='INTEGER', affinity='3', notNull=false, primaryKeyPosition=0, defaultValue='null'}, word=Column{name='word', type='text', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[]}

Then I used below mentioned code to solve that problem

@Entity(tableName = "enDic")
data class Word(

    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "_id")
    var _id: Int?,

    @ColumnInfo(name = "word")
    var word: String?,

    @ColumnInfo(name = "definition")
    var definition: String,

    @ColumnInfo(name = "favourite")
    var favourite: Int?,

    @ColumnInfo(name = "usage")
    var usage: Int?

)

Instead of this code

@Entity(tableName = "enDic")
data class Word(

    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "_id")
    var _id: Int,

    @ColumnInfo(name = "word")
    var word: String,

    @ColumnInfo(name = "definition")
    var definition: String,

    @ColumnInfo(name = "favourite")
    var favourite: Int,

    @ColumnInfo(name = "usage")
    var usage: Int

)

Answer:

if you want to add Integer type column , add this code

database.execSQL("ALTER TABLE users"
                    + " ADD COLUMN year INTEGER NOT NULL DEFAULT 0 ")