Question

我有一个名为str_train_no的字符串，我想创建一个名称相同的数据库，到目前为止我已经尝试了

        String name=str_Train_no+".db";
        SQLiteDatabase traindb = openOrCreateDatabase(name,SQLiteDatabase.CREATE_IF_NECESSARY , null);
        sql="CREATE TABLE IF NOT EXISTS "+str_Train_no+" ("
        +"Stops VARCHAR);";
        traindb.execSQL(sql);

下面是数据库声明和插入部分的源代码

SQLiteDatabase db = openOrCreateDatabase( "Train_list.db", SQLiteDatabase.CREATE_IF_NECESSARY , null);
    try {
        final String CREATE_TABLE_TRAIN_LIST = "CREATE TABLE IF NOT EXISTS Train_list ("
                + "Train_name VARCHAR,"
                + "Train_no VARCHAR,"
                + "Train_start VARCHAR,"
                + "Train_end VARCHAR,"
                + "Seats_Available VARCHAR);";
        db.execSQL(CREATE_TABLE_TRAIN_LIST);
        Toast.makeText(admin_manipulation.this, "Table created", Toast.LENGTH_LONG).show();
        String sql = "INSERT or replace INTO Train_list (Train_name, Train_no, Train_start, Train_end, Seats_Available) VALUES('"+str_Train_name + "',' " +str_Train_no + "', '" +str_Train_start+"','" +str_Train_end+"',' " +str_Train_seats +"');";
        db.execSQL(sql);
        Toast.makeText(admin_manipulation.this, "Inserted Sucessfully", Toast.LENGTH_SHORT).show();
        String name=str_Train_no+".db";
        SQLiteDatabase traindb = openOrCreateDatabase(name, SQLiteDatabase.CREATE_IF_NECESSARY , null);
        sql="CREATE TABLE IF NOT EXISTS "+str_Train_no+" ("
                +"Stops VARCHAR);";
        traindb.execSQL(sql);
        Toast.makeText(admin_manipulation.this, "Table "+str_Train_no+" verified", Toast.LENGTH_SHORT).show();
    }
    catch (Exception e) {
        Toast.makeText(admin_manipulation.this, "An Error has occured", Toast.LENGTH_SHORT).show();
    }

这会不断抛出异常。有什么想法吗？提前谢谢！

Answer 1

使用str_train_no数字字符串时，您遇到的问题是您尝试创建一个名称不是有效SQL标识符的表。

在这种特殊情况下，你可以通过在文本字符串前加上来解决它：

sql = "CREATE TABLE IF NOT EXISTS train"+str_Train_no+ ...

在您的情况下，您还可以使用静态表名，因为您为每列火车创建了一个数据库（这可能不是最好的事情）。

Answer 2

使用text而不是varchar。据我所知，SQLite中没有varchar。

如何从变量动态创建数据库？

2 个答案: