预填充房间数据库会引发错误 - 架构似乎是错误的

Question

I try to pre-populate a database in my Android application, but I get the following error:

 java.lang.IllegalStateException: Pre-packaged database has an invalid schema: Animal(com.example.application.db.Animal).
 Expected:
TableInfo{name='Animal', columns={gender=Column{name='gender', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, name=Column{name='name', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=1, defaultValue='null'}}, foreignKeys=[], indices=[]}
 Found:
TableInfo{name='Animal', columns={gender=Column{name='gender', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0, defaultValue='null'}, name=Column{name='name', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=1, defaultValue='null'}}, foreignKeys=[], indices=[]}

I really do not understand what's the problem, it seems to be absolute identical.

This is where in the code the error is thrown, when the db schema is compared to the entries it tries to insert:

  @Override
  protected RoomOpenHelper.ValidationResult onValidateSchema(SupportSQLiteDatabase _db) {
    final HashMap<String, TableInfo.Column> _columnsAnimal = new HashMap<String, TableInfo.Column>(2);
    _columnsAnimal.put("gender", new TableInfo.Column("gender", "TEXT", false, 0, null, TableInfo.CREATED_FROM_ENTITY));
    _columnsAnimal.put("name", new TableInfo.Column("name", "TEXT", true, 1, null, TableInfo.CREATED_FROM_ENTITY));
    final HashSet<TableInfo.ForeignKey> _foreignKeysAnimal = new HashSet<TableInfo.ForeignKey>(0);
    final HashSet<TableInfo.Index> _indicesAnimal = new HashSet<TableInfo.Index>(0);
    final TableInfo _infoAnimal = new TableInfo("Animal", _columnsAnimal, _foreignKeysAnimal, _indicesAnimal);
    final TableInfo _existingAnimal = TableInfo.read(_db, "Animal");
    if (! _infoAnimal.equals(_existingAnimal)) {  <<<<<<<<<this goes wrong, see next picture
      return new RoomOpenHelper.ValidationResult(false, "Animal(com.johndoes.animalsounds.db.Animal).\n"
              + " Expected:\n" + _infoAnimal + "\n"
              + " Found:\n" + _existingAnimal);
    }

Location where image is thrown

This is my entity class:

import androidx.annotation.NonNull;
import androidx.room.ColumnInfo;
import androidx.room.Entity;
import androidx.room.PrimaryKey;

@Entity(tableName = "Animal")
public class Animal {

@ColumnInfo(name = "gender")
public final String gender;

@PrimaryKey
@NonNull
@ColumnInfo(name = "name")
public final String name;


public Animal(@NonNull String  name, String gender) {
    this.name = name;
    this.gender = gender;
}
}

And this is the SQL that created the sqlite table that I want to preload:

CREATE TABLE "Animal" (
"name"  TEXT,
"gender"    TEXT,
PRIMARY KEY("name")
);

Any ideas would be highly appreciated, thank you.

Answer 1

as I understood you said your primary key is name but it is absolutely wrong, not even that you defined it as text, the text datatype in database is always nullable you should define a long datatype as your table id and add it as primary key and also remove not null attribute from animal names.

on your sqlite add "name" TEXT NOT NULL

hope this helps