Can't migrate a table to Room do to an error with the way booleans is saved in Sqlite
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【中文标题】Can\'t migrate a table to Room do to an error with the way booleans is saved in Sqlite【英文标题】：Can't migrate a table to Room do to an error with the way booleans are saved in SqliteCan't migrate a table to Room do to an error with the way booleans is saved in Sqlite 【发布时间】：2019-10-05 05:36:07 【问题描述】：我一直在尝试将我的应用迁移到 Room。我正在为一个无法直接迁移的特定表而苦苦挣扎，因为它的创建方式。
这些字段是使用数据类型 BOOL 和 BYTE 而不是 INTEGER 创建的。
我已经尝试失败了：
将我的实体字段更改为 Int/Boolean/Byte 时出现相同错误 创建 TypeConverter 以将其保存为布尔值/字节 将typeAffinity 添加为UNDEFINED 在我的亲和度= 1 的实体的@ColumnInfo 中
我的databaseSQL造句：
CREATE TABLE IF NOT EXISTS myTable (_id INTEGER PRIMARY KEY AUTOINCREMENT,
my_first_field BOOL NOT NULL DEFAULT 0,
my_second_field BYTE NOT NULL DEFAULT 0)
我的实体：
@Entity(tableName = "myTable")
data class MyTable(
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "_id")
var id: Int,
@ColumnInfo(name = "my_first_field")
var myFirstField: Boolean = false,
@ColumnInfo(name = "my_second_field")
var mySecondField: Byte = false
)
我经常遇到的错误是：
Expected:
TableInfoname='my_table', columns=_id=Columnname='_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, my_first_field=Columnname='my_first_field', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, my_second_field=Columnname='my_second_field', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, foreignKeys=[], indices=[]
Found:
TableInfoname='my_table', columns=_id=Columnname='_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, my_first_field=Columnname='my_first_field', type='BOOL', affinity='1', notNull=true, primaryKeyPosition=0, my_second_field=Columnname='my_second_field', type='BYTE', affinity='1', notNull=true, primaryKeyPosition=0, foreignKeys=[], indices=[]
有没有什么方法可以在不创建迁移策略的情况下直接进行？
【问题讨论】：
请添加更多代码！ @mohammadRezaAbiri 您认为还有哪些有用/必要的代码？ Sqlite 没有“布尔”或“字节”类型...使用整数。 sqlite.org/datatype3.html 我知道 SQLITE 没有布尔值或字节。实际上，如果数据库是新的，则不会发生此错误，因为数据库字段被初始化为 INTEGER 而不是 BYTE 或 BOOL。我的问题是如何避免破坏我的表并将信息复制到新表中。 【参考方案1】：我相信你可以，在构建房间数据库之前：-
检查是否需要做任何事情，例如通过使用：-
SELECT count() FROM sqlite_master WHERE name = 'myTable' AND instr(sql,' BOOL ') AND instr(sql,' BYTE ');
然后检查结果。
如果它为 0，则什么也不做（尽管为了安全起见，您只能在 oldmyTable 为 0 时使用 DROP TABLE IF EXISTS oldmyTable）。
仅如果以上返回 1 则：-
删除重命名的原始表（见下文和上文）以防万一它存在：-
DROP TABLE IF EXISTS oldmyTable;
使用
定义另一个表CREATE TABLE IF NOT EXISTS myOtherTable (_id INTEGER PRIMARY KEY AUTOINCREMENT,
my_first_field INTEGER NOT NULL DEFAULT 0,
my_second_field INTEGER NOT NULL DEFAULT 0)
即预期的架构
使用
填充新表INSERT INTO myOtherTable SELECT * FROM myTable;
使用 :-
重命名 mytableALTER TABLE mytable RENAME TO oldmyTable;
使用原始名称重命名 myOtherTable :-
ALTER TABLE myOtherTable RENAME TO mytable;
删除重命名的原始表（显然仅在测试时）：-
DROP TABLE IF EXISTS oldmyTable;
最终结果是表格应该是预期的。
关于评论：-
问题是我有 16-20 个表要迁移。
你可以使用类似的东西：-
public static int preMigrateAdjustment(SQLiteDatabase mDB)
String original_rename_prefix = "old";
String tempname_suffix = "temp";
String newsql_column = "newsql";
String[] columns = new String[]
"name",
"replace(replace(sql,' BOOL ',' INTEGER '),' BYTE ',' INTEGER ') AS " + newsql_column
;
int count_done = 0;
String whereclause = "name LIKE('" +
original_rename_prefix +
"%') AND type = 'table'";
Cursor csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
while (csr.moveToNext())
mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
whereclause = "type = 'table' AND (instr(sql,' BOOL ') OR instr(sql,' BYTE '))";
csr = mDB.query(
"sqlite_master",
columns,
whereclause,
null,null,null,null
);
while (csr.moveToNext())
String base_table_name = csr.getString(csr.getColumnIndex("name"));
String newsql = csr.getString(csr.getColumnIndex(newsql_column));
String temp_table_name = base_table_name + tempname_suffix;
String renamed_table_name = original_rename_prefix+base_table_name;
mDB.execSQL(newsql.replace(base_table_name,temp_table_name));
mDB.execSQL("INSERT INTO " + temp_table_name + " SELECT * FROM " + base_table_name);
mDB.execSQL("ALTER TABLE " + base_table_name + " RENAME TO " + renamed_table_name);
mDB.execSQL("ALTER TABLE " + temp_table_name + " RENAME TO " + base_table_name);
count_done++;
whereclause = "name LIKE('" +
original_rename_prefix +
"%') AND type = 'table'";
csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
while (csr.moveToNext())
mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
csr.close();
return count_done;
附加
在解决 BOOL BYTE 类型后，研究这个并实际测试（在本例中使用 5 个表）具有相同架构的另一个问题出现在该编码中
_id INTEGER PRIMARY KEY AUTOINCREMENT
导致notNull = false，同时编码
@PrimaryKey(autoGenerate = true)
private long _id;
导致 notNull=true
例如假设 AUTOINCREMENT NOT NULL 未编码的快速修复 preMigrateAdjustment 中的行已从 :-
mDB.execSQL((newsql.replace(base_table_name,temp_table_name)));
到：-
mDB.execSQL((newsql.replace(base_table_name,temp_table_name)).replace("AUTOINCREMENT","AUTOINCREMENT NOT NULL"));
工作演示
创建和填充旧的（房间前）表。
在 Database Helper OrginalDBHelper.java 中创建和填充旧表：-
public class OriginalDBHelper extends SQLiteOpenHelper
public static final String DBNAME = "mydb";
public static final int DBVERSION = 1;
int tables_to_create = 5; //<<<<<<<<<< 5 sets of tables
SQLiteDatabase mDB;
public OriginalDBHelper(Context context)
super(context, DBNAME, null, DBVERSION);
mDB = this.getWritableDatabase();
@Override
public void onCreate(SQLiteDatabase db)
for (int i=0;i < tables_to_create;i++)
db.execSQL("CREATE TABLE IF NOT EXISTS myTable" + String.valueOf(i) + "X (_id INTEGER PRIMARY KEY AUTOINCREMENT,\n" +
" my_first_field BOOL NOT NULL DEFAULT 0,\n" +
" my_second_field BYTE NOT NULL DEFAULT 0)"
);
db.execSQL("INSERT INTO myTable" + String.valueOf(i) + "X (my_first_field,my_second_field) VALUES(0,0),(1,0),(1,1),(0,1)");
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
表的迁移前转换
即调整架构以适应房间）PreMigrationAdjustment.java
public class PreMigrationAdjustment
public static int preMigrateAdjustment(SQLiteDatabase mDB)
String original_rename_prefix = "old";
String tempname_suffix = "temp";
String newsql_column = "newsql";
String[] columns = new String[]
"name",
"replace(replace(sql,' BOOL ',' INTEGER '),' BYTE ',' INTEGER ') AS " + newsql_column
;
int count_done = 0;
String whereclause = "name LIKE('" +
original_rename_prefix +
"%') AND type = 'table'";
Cursor csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
while (csr.moveToNext())
mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
whereclause = "type = 'table' AND (instr(sql,' BOOL ') OR instr(sql,' BYTE '))";
csr = mDB.query(
"sqlite_master",
columns,
whereclause,
null,null,null,null
);
while (csr.moveToNext())
String base_table_name = csr.getString(csr.getColumnIndex("name"));
String newsql = csr.getString(csr.getColumnIndex(newsql_column));
String temp_table_name = base_table_name + tempname_suffix;
String renamed_table_name = original_rename_prefix+base_table_name;
mDB.execSQL((newsql.replace(base_table_name,temp_table_name)).replace("AUTOINCREMENT","AUTOINCREMENT NOT NULL"));
//mDB.execSQL((newsql.replace(base_table_name,temp_table_name)));
mDB.execSQL("INSERT INTO " + temp_table_name + " SELECT * FROM " + base_table_name);
mDB.execSQL("ALTER TABLE " + base_table_name + " RENAME TO " + renamed_table_name);
mDB.execSQL("ALTER TABLE " + temp_table_name + " RENAME TO " + base_table_name);
count_done++;
whereclause = "name LIKE('" +
original_rename_prefix +
"%') AND type = 'table'";
csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
while (csr.moveToNext())
mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
csr.close();
return count_done;
房间的实体
为简洁起见，仅显示 5 个中的 1 个，即 myTable0X.java
显然，这些必须仔细编写以匹配前厅表。
@Entity()
public class myTable0X
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "_id")
private long id;
@ColumnInfo(name = "my_first_field")
private boolean my_first_field;
@ColumnInfo(name = "my_second_field")
private boolean my_second_field;
public long getId()
return id;
public void setId(long id)
this.id = id;
public boolean isMy_first_field()
return my_first_field;
public void setMy_first_field(boolean my_first_field)
this.my_first_field = my_first_field;
public boolean isMy_second_field()
return my_second_field;
public void setMy_second_field(boolean my_second_field)
this.my_second_field = my_second_field;
单个 DAO 接口 DAOmyTablex.java
@Dao
public interface DAOmyTablex
@Query("SELECT * FROM myTable0X")
List<myTable0X> getAllFrommyTable0();
@Query("SELECT * FROM myTable1X")
List<myTable1X> getAllFrommyTable1();
@Query("SELECT * FROM myTable2X")
List<myTable2X> getAllFrommyTable2();
@Query("SELECT * FROM myTable3X")
List<myTable3X> getAllFrommyTable3();
@Query("SELECT * FROM myTable4X")
List<myTable4X> getAllFrommyTable4();
@Insert
long[] insertAll(myTable0X... myTable0XES);
@Insert
long[] insertAll(myTable1X... myTable1XES);
@Insert
long[] insertAll(myTable2X... myTable2XES);
@Insert
long[] insertAll(myTable3X... myTable3XES);
@Insert
long[] insertAll(myTable4X... myTable4XES);
@Delete
int delete(myTable0X mytable0X);
@Delete
int delete(myTable1X mytable1X);
@Delete
int delete(myTable2X mytable2X);
@Delete
int delete(myTable3X mytable3X);
@Delete
int delete(myTable4X mytable4X);
数据库 mydb.java
@Database(entities = myTable0X.class, myTable1X.class, myTable2X.class, myTable3X.class, myTable4X.class,version = 2)
public abstract class mydb extends RoomDatabase
public abstract DAOmyTablex dbDAO();
把它们放在一起MainActivity.java
这包括 3 个核心阶段
-
构建前房数据库。
将桌子改造成适合房间。
通过房间打开（移交）数据库。
当应用启动时，它会自动执行第 1 阶段和第 2 阶段，添加了一个按钮，点击该按钮后将执行第 3 阶段（仅一次）。
最后，从表中提取数据（这实际上打开了 Room 数据库） 并将其中一张表中的数据输出到日志中。
public class MainActivity extends AppCompatActivity
OriginalDBHelper mDBHlpr;
Button mGo;
mydb mMyDB;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mGo = this.findViewById(R.id.go);
mGo.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
goForIt();
);
mDBHlpr = new OriginalDBHelper(this);
Log.d("STAGE1","The original tables");
dumpAllTables();
Log.d("STAGE2", "Initiaing pre-mirgration run.");
Log.d("STAGE2 A RESULT",
String.valueOf(
PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
)
) + " tables converted."
); //<<<<<<<<<< CONVERT THE TABLES
Log.d("STAGE2 B","Dumping adjusted tables");
dumpAllTables();
Log.d("STAGE2 C","Second run Cleanup");
Log.d("STAGE2 DRESULT",
String.valueOf(
PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
)
) + " tables converted."
); //<<<<<<<<<< CONVERT THE TABLES
dumpAllTables();
Log.d("STAGE3","Handing over to ROOM (when button is clicked)");
private void goForIt()
if (mMyDB != null) return;
mMyDB = Room.databaseBuilder(this,mydb.class,OriginalDBHelper.DBNAME).addMigrations(MIGRATION_1_2).allowMainThreadQueries().build();
List<myTable0X> mt0 = mMyDB.dbDAO().getAllFrommyTable0();
List<myTable1X> mt1 = mMyDB.dbDAO().getAllFrommyTable1();
List<myTable2X> mt2 = mMyDB.dbDAO().getAllFrommyTable2();
List<myTable3X> mt3 = mMyDB.dbDAO().getAllFrommyTable3();
List<myTable4X> mt4 = mMyDB.dbDAO().getAllFrommyTable4();
for (myTable0X mt: mt0)
Log.d("THIS_MT","ID is " + String.valueOf(mt.getId()) + " FIELD1 is " + String.valueOf(mt.isMy_first_field()) + " FIELD2 is " + String.valueOf(mt.isMy_second_field()));
// etc.......
private void dumpAllTables()
SQLiteDatabase db = mDBHlpr.getWritableDatabase();
Cursor c1 = db.query("sqlite_master",null,"type = 'table'",null,null,null,null);
while (c1.moveToNext())
Log.d("TABLEINFO","Dmuping Data for Table " + c1.getString(c1.getColumnIndex("name")));
Cursor c2 = db.query(c1.getString(c1.getColumnIndex("name")),null,null,null,null,null,null);
DatabaseUtils.dumpCursor(c2);
c2.close();
c1.close();
public final Migration MIGRATION_1_2 = new Migration(1, 2)
@Override
public void migrate(SupportSQLiteDatabase database)
/**NOTES
//Tried the pre-migration here BUT SQLiteDatabaseLockedException: database is locked (code 5 SQLITE_BUSY)
//Cannot use SupportSQLiteDatabase as that locks out access to sqlite_master
//PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Initial run
//PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Cleanup run
*/
;
结果
结果（只是 STAGE???? 输出）是：-
2019-05-19 13:18:12.227 D/STAGE1: The original tables
2019-05-19 13:18:12.244 D/STAGE2: Initiaing pre-mirgration run.
2019-05-19 13:18:12.281 D/STAGE2 A RESULT: 5 tables converted.
2019-05-19 13:18:12.281 D/STAGE2 B: Dumping adjusted tables
2019-05-19 13:18:12.303 D/STAGE2 C: Second run Cleanup
2019-05-19 13:18:12.304 D/STAGE2 DRESULT: 0 tables converted.
2019-05-19 13:18:12.331 D/STAGE3: Handing over to ROOM (when button is clicked)
决赛排是：-
2019-05-19 13:20:03.090 D/THIS_MT: ID is 1 FIELD1 is false FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 2 FIELD1 is true FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 3 FIELD1 is true FIELD2 is true
2019-05-19 13:20:03.090 D/THIS_MT: ID is 4 FIELD1 is false FIELD2 is true
【讨论】：
这是我管理它的实际方式，因为除了迁移它似乎别无他法。问题是数据库已经创建并填充。问题是我要迁移 16-20 个表。很多。如果没有更好的答案，或者有什么直接的方法，我会投票并选择它作为正确答案。 @AndresOller 您可以使用SELECT name, replace(replace(sql,' BOOL ',' INTEGER '),' BYTE ',' INTEGER ') AS newsql FROM sqlite_master WHERE instr(sql,' BOOL ') OR instr(sql,' BYTE '); 之类的东西来驱动多表进程。所以对于每一行（如果没有，什么也不做）你有表名和调整后的 SQL。以上是关于Can't migrate a table to Room do to an error with the way booleans is saved in Sqlite的主要内容，如果未能解决你的问题，请参考以下文章
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