Question

我正在从数据库的所有表中搜索批量删除。

DELETE FROM TABLE1,TABLE2,TABLE3; --(Is it possible)

像我们有批量插入一样

INSERT INTO TABLE (a,b,c) VALUES (1,2,3),(4,5,6),(7,8,9);

我不满意的代码就像这样。它能够做到这一点。

Delete from table1;
Delete from table2;
Delete from table3;

public void truncateDatabase() {
    ArrayList<String> tables = new ArrayList<>();
    Cursor cursor = Database.getInstance().getWritableDatabase().rawQuery("SELECT name FROM sqlite_master WHERE type='table'", null);
    if (cursor.moveToFirst()) {
        while (!cursor.isAfterLast()) {
            tables.add(cursor.getString(0));
            cursor.moveToNext();
        }
    }
    cursor.close();

    for (String table : tables) {
        Database.getInstance().getWritableDatabase().execSQL("DELETE FROM " + table);
        Database.getInstance().getWritableDatabase().execSQL("VACUUM");
    }
}

Answer 1

如documentation所示，单个DELETE语句适用于单个表。

执行多个DELETE语句没有错。

但是，您应该只执行一次VACUUM，并考虑使用事务：

SQLiteDatabase db = Database.getInstance().getWritableDatabase();
db.beginTransaction();
try {
    for (String table : tables) {
        db.execSQL("DELETE FROM " + table);
    }
    db.setTransactionSuccessful();
} finally {
    db.endTransaction();
}
db.execSQL("VACUUM");

如何在单个命令中使用sqllite截断数据库（清除数据库中所有表的记录）

1 个答案: