SQLite - 跨数据库查询不起作用
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【中文标题】SQLite - 跨数据库查询不起作用【英文标题】：SQLite - Cross Database Query not working 【发布时间】：2018-04-15 20:40:41 【问题描述】：我想在 android 的 SQLite 中执行跨数据库查询。我在两个不同的数据库中有两个表。
attach database 'data/data/com.app/databases/db1' as db1;
attach database 'data/data/com.app/databases/db2' as db2;
SELECT db1.tbl1.* FROM db1.tbl1 JOIN db2.tbl2 ON db1.tbl1.primaryKey = db2.tbl2.primaryKey
WHERE db1.tbl1.columnX = ? AND db2.tbl2.columnY = ?
通过使用 Android rawQuery 方法调用此查询，例如：
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, new String[]"1","xyz");
我收到此错误：
SQLiteException: bind or column index out of range: handle 0xa6259ec8
我检查了查询的语法，它是正确的。 Android中不能执行跨库查询吗？
【问题讨论】：
查看***.com/a/4499816/3364266 @SamirBhatt 是的，打开多个数据库工作正常，但查询数据不起作用。 相同的 db 文件：将数据库 'data/data/com.app/databases/db1' 附加为 db1；将数据库 'data/data/com.app/databases/db1' 附加为 db2; @ViktorYakunin 抱歉，这是我的错字。已更正 【参考方案1】：我检查了查询的语法，它是正确的。是不是不可能 在Android中执行跨数据库查询？
是的，正如所包含的示例所展示的那样。
我认为您的问题是您似乎使用了不正确的rawQuery 方法/签名。
而不是：-
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, "1","xyz");
我相信你应该使用：-
Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, new String[]"1","xyz");
前者仅提供 1 个绑定项，而不是两个预期的绑定项（尽管您使用的甚至不是 rawQuery 的有效签名）
但是，我确实怀疑，通过测试您在查询方面还有其他问题。这是一个基于您的原始帖子的工作示例（即附加的数据库实际上是相同的数据库，但这在原则上应该无关紧要）：-
public class MainActivity extends AppCompatActivity
public static final String DBNAME1 = "db1";
public static final String DBNAME2 = "db2";
public static final String DBNAME3 = "db3";
public static final String ID_COLUMN = "_id";
public static final String TABLENAME_BASE = "_table_main";
public static final String NAMECOLUMN_BASE = "_name";
public static final String DB2_COL_NAME = DBNAME2 + NAMECOLUMN_BASE;
public static final String EXTENDED_DB2TABLENAME = DBNAME2 + "." + DBNAME2 + TABLENAME_BASE;
public static final String EXTENDED_DB3TABLENAME = DBNAME3 + "." + DBNAME2 + TABLENAME_BASE;
public static final String DB2_FULL_IDCOL = EXTENDED_DB2TABLENAME + "." + ID_COLUMN;
public static final String DB2_FULL_NAMECOL = EXTENDED_DB2TABLENAME + "." + DBNAME2 + NAMECOLUMN_BASE;
public static final String DB3_FULL_IDCOL = EXTENDED_DB3TABLENAME + "." + ID_COLUMN;
public static final String DB3_FULL_NAMECOL = EXTENDED_DB3TABLENAME + "." + DBNAME2 + NAMECOLUMN_BASE;
private static final String[] DB1NAMES = new String[] "Fred","Bert","Harry","Tom","Dick";
private static final String[] DB2NAMES = new String[] "Alan","George","Robert","Colin","Ian","John";
String mDB1Path, mDB2path;
SQLiteDatabase mMaster;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDB1Path = createDatbase(DBNAME1);
mDB2path = createDatbase(DBNAME2);
/* Just to add some data for 1st run
for (String s: DB2NAMES)
insertRow(DBNAME1,s);
for (String s: DB1NAMES)
insertRow(DBNAME2,s);
*/
// Open the main database and attach databases
mMaster = this.openOrCreateDatabase(mDB1Path, Context.MODE_PRIVATE,null);
String attachsql = "ATTACH DATABASE '" + mDB2path + "' AS " + DBNAME2;
String attachsql2 = "ATTACH DATABASE '" + mDB2path + "' AS " + DBNAME3;
mMaster.execSQL(attachsql);
mMaster.execSQL(attachsql2);
// Prepare first query between all 3 DB's
String sqlstr = "SELECT " +
DBNAME1 + TABLENAME_BASE + ".*, " +
DBNAME2 + "." + DBNAME2 + TABLENAME_BASE + "." + DB2_COL_NAME +
", " + DBNAME3 + "." + DBNAME2 + TABLENAME_BASE + "." + DB2_COL_NAME +
" FROM " + DBNAME1 + TABLENAME_BASE +
" JOIN " + DBNAME2 + "." + DBNAME2 + TABLENAME_BASE +
" ON " + DBNAME1 + TABLENAME_BASE + "." + ID_COLUMN +
" = " + DBNAME2 + "." + DBNAME2 + TABLENAME_BASE + "." + ID_COLUMN +
" JOIN " + DBNAME3 + "." + DBNAME2 + TABLENAME_BASE +
" ON " + DBNAME1 + TABLENAME_BASE + "." + ID_COLUMN +
" = " + DBNAME3 + "." + DBNAME2 + TABLENAME_BASE + "." + ID_COLUMN;
// Write query string to log
Log.d("SELECTSQL_1",sqlstr);
// Perform the query an write resultant data to the log
Cursor csr = mMaster.rawQuery(sqlstr,null);
while (csr.moveToNext())
String logdata = "Row = " + csr.getPosition();
for (int i=0; i < csr.getColumnCount(); i++)
logdata = logdata + " Column = " + csr.getColumnName(i) +
" Value = " + csr.getString(i);
Log.d("CSRINFO",logdata);
// Arguments for 2nd query
String arg1 = "12";
String arg2 = "Fred";
// SQL for 2nd query including WHERE clause
String sqlstr2 = " SELECT " +
DB2_FULL_IDCOL + ", " +
DB2_FULL_NAMECOL + ", " +
DB3_FULL_IDCOL + ", " +
DB3_FULL_NAMECOL +
" FROM " + DBNAME2 + TABLENAME_BASE +
" JOIN " + DBNAME3 + "." + DBNAME2 + TABLENAME_BASE +
" ON " + DBNAME2 + "." + DBNAME2 + TABLENAME_BASE + "." + ID_COLUMN +
" = " + DB3_FULL_IDCOL +
" WHERE " +
DB3_FULL_IDCOL + "=? AND " +
DB3_FULL_NAMECOL + "=?";
// Log the query string
Log.d("SELECTSQL_2",sqlstr2);
// Perform 2nd query and log cursor result
Cursor csr2 = mMaster.rawQuery(sqlstr2,new String[]arg1,arg2);
while (csr2.moveToNext())
String logdata = "Row = " + csr2.getPosition();
for (int i=0; i < csr2.getColumnCount(); i++)
logdata = logdata + " Column = " + csr2.getColumnName(i) +
" Value = " + csr2.getString(i);
Log.d("CSRINFO",logdata);
// Used to create the two actual databases
private String createDatbase(String dbqualifier)
SQLiteDatabase db = this.openOrCreateDatabase(dbqualifier,Context.MODE_PRIVATE,null);
String tblcrtstr = "CREATE TABLE IF NOT EXISTS " +
dbqualifier + TABLENAME_BASE +
"(" +
ID_COLUMN + " INTEGER PRIMARY KEY, " +
dbqualifier + NAMECOLUMN_BASE + " TEXT" +
")";
db.execSQL(tblcrtstr);
String rv = db.getPath();
db.close();
return rv;
// Insert a row to the respective database
private void insertRow(String dbqualifier, String name)
SQLiteDatabase db = this.openOrCreateDatabase(dbqualifier,MODE_PRIVATE,null);
ContentValues cv = new ContentValues();
cv.put(dbqualifier + NAMECOLUMN_BASE, name);
db.insert(dbqualifier + TABLENAME_BASE,null,cv);
db.close();
我相信您主要对第二个查询感兴趣：-
SELECT db2.db2_table_main._id, db2.db2_table_main.db2_name, db3.db2_table_main._id, db3.db2_table_main.db2_name FROM db2_table_main JOIN db3.db2_table_main ON db2.db2_table_main._id = db3.db2_table_main._id WHERE db3.db2_table_main._id=? AND db3.db2_table_main.db2_name=?
请注意，上面的查询是基于原始帖子，其中两次附加了相同的数据库。
运行上述代码（经过多次运行，包括注释掉的行插入代码）产生了以下结果：-
来自/对于第一个查询：-
11-05 07:37:52.764 2726-2726/? D/SELECTSQL_1: SELECT db1_table_main.*, db2.db2_table_main.db2_name, db3.db2_table_main.db2_name FROM db1_table_main JOIN db2.db2_table_main ON db1_table_main._id = db2.db2_table_main._id JOIN db3.db2_table_main ON db1_table_main._id = db3.db2_table_main._id
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 0 Column = _id Value = 1 Column = db1_name Value = Fred Column = db2_name Value = Alan Column = db2_name Value = Alan
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 1 Column = _id Value = 2 Column = db1_name Value = Bert Column = db2_name Value = George Column = db2_name Value = George
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 2 Column = _id Value = 3 Column = db1_name Value = Harry Column = db2_name Value = Robert Column = db2_name Value = Robert
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 3 Column = _id Value = 4 Column = db1_name Value = Tom Column = db2_name Value = Colin Column = db2_name Value = Colin
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 4 Column = _id Value = 5 Column = db1_name Value = Dick Column = db2_name Value = Ian Column = db2_name Value = Ian
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 5 Column = _id Value = 6 Column = db1_name Value = Alan Column = db2_name Value = John Column = db2_name Value = John
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 6 Column = _id Value = 7 Column = db1_name Value = George Column = db2_name Value = Fred Column = db2_name Value = Fred
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 7 Column = _id Value = 8 Column = db1_name Value = Robert Column = db2_name Value = Bert Column = db2_name Value = Bert
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 8 Column = _id Value = 9 Column = db1_name Value = Colin Column = db2_name Value = Harry Column = db2_name Value = Harry
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 9 Column = _id Value = 10 Column = db1_name Value = Ian Column = db2_name Value = Tom Column = db2_name Value = Tom
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 10 Column = _id Value = 11 Column = db1_name Value = John Column = db2_name Value = Dick Column = db2_name Value = Dick
11-05 07:37:52.764 2726-2726/? D/CSRINFO: Row = 11 Column = _id Value = 12 Column = db1_name Value = Alan Column = db2_name Value = Fred Column = db2_name Value = Fred
11-05 07:37:52.765 2726-2726/? D/CSRINFO: Row = 12 Column = _id Value = 13 Column = db1_name Value = George Column = db2_name Value = Bert Column = db2_name Value = Bert
11-05 07:37:52.765 2726-2726/? D/CSRINFO: Row = 13 Column = _id Value = 14 Column = db1_name Value = Robert Column = db2_name Value = Harry Column = db2_name Value = Harry
11-05 07:37:52.765 2726-2726/? D/CSRINFO: Row = 14 Column = _id Value = 15 Column = db1_name Value = Colin Column = db2_name Value = Tom Column = db2_name Value = Tom
11-05 07:37:52.765 2726-2726/? D/CSRINFO: Row = 15 Column = _id Value = 16 Column = db1_name Value = Ian Column = db2_name Value = Dick Column = db2_name Value = Dick
从带有 WHERE 子句的第二个查询：-
11-05 07:37:52.765 2726-2726/? D/SELECTSQL_2: SELECT db2.db2_table_main._id, db2.db2_table_main.db2_name, db3.db2_table_main._id, db3.db2_table_main.db2_name FROM db2_table_main JOIN db3.db2_table_main ON db2.db2_table_main._id = db3.db2_table_main._id WHERE db3.db2_table_main._id=? AND db3.db2_table_main.db2_name=?
11-05 07:37:52.765 2726-2726/? D/CSRINFO: Row = 0 Column = _id Value = 12 Column = db2_name Value = Fred Column = _id Value = 12 Column = db2_name Value = Fred
即它只选择了 16 行中的一行，即 _id 列中有 12 和 Fred 的一行> 在第二个附加 (db3) 数据库的 名称 列中。
【讨论】：
这是一个错字。你能帮忙吗？以上是关于SQLite - 跨数据库查询不起作用的主要内容，如果未能解决你的问题，请参考以下文章
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