我正在将我的数据库从版本3升级到版本4,并通过提供从版本3到版本4的迁移来完成。
以下是我的迁移代码:
private static Migration MIGRATION_3_4 = new Migration(3, 4) {
@Override
public void migrate(@NonNull SupportSQLiteDatabase database) {
database.execSQL("ALTER TABLE caption_table ADD COLUMN localVideoUrl TEXT;");
database.execSQL("ALTER TABLE caption_table ADD COLUMN postType TEXT");
database.execSQL("ALTER TABLE caption_table ADD COLUMN videoUrl TEXT");
}
};
这是创建房间数据库的代码:
this.mAppDataBase = Room.databaseBuilder(getApplicationContext(), AppDataBase.class, "my_db")
.addMigrations(MIGRATION_2_3, MIGRATION_3_4)
.build();
这是我在PostModel上添加的代码片段。
@Expose
private String postType;
@Expose
private String videoUrl;
@Expose
private String localVideoUrl;
public String getPostType() {
return postType;
}
public void setPostType(String postType) {
this.postType = postType;
}
public String getVideoUrl() {
return videoUrl;
}
public void setVideoUrl(String videoUrl) {
this.videoUrl = videoUrl;
}
public String getLocalVideoUrl() {
return localVideoUrl;
}
public void setLocalVideoUrl(String localVideoUrl) {
this.localVideoUrl = localVideoUrl;
}
以下是我得到的错误信息。该错误与房间实体的notNull属性无关。 ``` java.lang.IllegalStateException: 迁移未正确处理posts(com.myapp.Database.PostModel)。 预期: TableInfo{name='posts', columns={imageWidth=Column{name='imageWidth', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}, localVideoUrl=Column{name='localVideoUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, authorImageLocalUrl=Column{name='authorImageLocalUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, videoUrl=Column{name='videoUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageLocalUrl=Column{name='imageLocalUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, postType=Column{name='postType', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, authorName=Column{name='authorName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageUrl=Column{name='imageUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1}, title=Column{name='title', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, authorImageUrl=Column{name='authorImageUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageHeight=Column{name='imageHeight', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}}, foreignKeys=[], indices=[]} 找到: TableInfo{name='posts', columns={imageWidth=Column{name='imageWidth', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}, authorImageLocalUrl=Column{name='authorImageLocalUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageLocalUrl=Column{name='imageLocalUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, authorName=Column{name='authorName', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageUrl=Column{name='imageUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, id=Column{name='id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1}, title=Column{name='title', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, authorImageUrl=Column{name='authorImageUrl', type='TEXT', affinity='2', notNull=false, primaryKeyPosition=0}, imageHeight=Column{name='imageHeight', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}}, foreignKeys=[], indices=[]} ```