Room Database Migration doesnt properly handle ALTER TABLE migration

Question

Java.lang.IllegalStateException

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

Expected:

TableInfo{n

Answer 1

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

)