在Android上创建多个SQLite表

Question

你好，我想在数据库中创建两个不同的表，这些表分别是User_details和Creditcard_details。我已经创建了以下DBAdapter类来实现数据库操作，但是当我调用insertCreditcard()方法时，值没有被插入。我想知道第二个表是否被创建。我做错了什么，但无法确定错误所在，我应该怎么做才能纠正这个问题。

我想要做的是从登录活动中提供的用户名和密码检查User_details表中的id字段，然后将这个id变量的值赋给另一个名为ccid的变量，该变量用于搜索Creditcard_details表中的行或插入值。

请问有人可以指导我吗？

    package com.androidbook.LoginForm;

    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.SQLException;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
        import android.util.Log;
        import android.widget.Toast;


public class DBAdapter {
        /*------------------------User Details ---------------------------------*/
        public static Cursor d;
        public static final String KEY_ROWID = "_id";
        public static final String KEY_Name = "name";
        public static final String KEY_Username = "username";
        public static final String KEY_Password = "password";

        private static final String TAG = "DBAdapter";

        private static final String DATABASE_NAME = "Wallet";
        private static final String DATABASE_TABLE = "User_Details";

        /*------------------------Credit Cards Table----------------------*/

        private static final String KEY_CCID = "_ccid";
        private static final String KEY_CCUNAME= "cuname";
        private static final String KEY_CCNO = "ccno";
        private static final String KEY_CVV  = "cvvno";
        private static final String EXP_DATE = "expdate";
        private static final String CREDITCARDS_TABLE = "Creditcard_Details";

        private static final int DATABASE_VERSION = 1;

        private static final String DATABASE_CREATE =
            "create table User_Details (_id integer primary key autoincrement, "
            + "name text not null, username text not null, " 
            + "password text not null);";

        /*---------------------Create Credit Card Table -------------------------------*/
        private static final String CCTABLE_CREATE =
            "create table Creditcard_Details ( _ccid integer primary key , "
            + "cuname text not null, ccno text not null, " 
            + "cvvno text not null" + "expdate text not null )";//+ "FOREIGN KEY(_ccid) REFERENCES User_Details(_id))";

        private final Context context;  
        public DatabaseHelper DBHelper;
        private SQLiteDatabase db;

        public DBAdapter(Context ctx) 
        {
            this.context = ctx;
            DBHelper = new DatabaseHelper(context);
        }

        private static class DatabaseHelper extends SQLiteOpenHelper 
        {
            DatabaseHelper(Context context) 
            {
                super(context, DATABASE_NAME, null, DATABASE_VERSION);
            }

            @Override
            public void onCreate(SQLiteDatabase db) 
            {
                db.execSQL(DATABASE_CREATE);
                db.execSQL(CCTABLE_CREATE);

            }

            @Override
            public void onUpgrade(SQLiteDatabase db, int oldVersion, 
                                  int newVersion) 
            {
                Log.w(TAG, "Upgrading database from version " + oldVersion 
                      + " to "
                      + newVersion + ", which will destroy all old data");
                db.execSQL("DROP TABLE IF EXISTS titles");
                onCreate(db);
            }
        }
        public int Login(String username,String password)
        {
        try
        {
            Cursor c = null;
            c = db.rawQuery("select * from User_Details where username =" + "\""+ username + "\""+" and password="+ "\""+ password + "\"", null);
            c.moveToFirst(); 
            String tempid = c.getString(0);
            //Toast.makeText(DBAdapter.this, "correct"+" "+c,Toast.LENGTH_LONG).show();
            d= c;//CCview(tempid);
            return c.getCount(); 
        } 
        catch(Exception e) 
        { 
            e.printStackTrace();
            }

        return 0; 
        }


        //-----------------------Display Credit Card -----------------------------

       /* public int Getid(String tempid)
        {   Cursor c;
            c = db.rawQuery("select id from User_Details where username ="
                    + "\""+ username + "\"", null);

            return Integer.parseInt(c.getString(0));

        }*/
        public Cursor cursordisplay()
        { return d;

        } 


        public Cursor CCview(long menuid)throws SQLException 

        {

            Cursor mCursor =
                    db.query(true, CREDITCARDS_TABLE, new String[] {
                            KEY_CCID,
                            KEY_CCUNAME, 
                            KEY_CCNO,
                            KEY_CVV,
                            EXP_DATE,
                            }, 
                            KEY_CCID + "=" + menuid, 
                            null,
                            null, 
                            null, 
                            null, 
                            null);
            if (mCursor != null) {
                mCursor.moveToFirst();
            }
            return mCursor;
        }



        //--------------------Entries into Credit Card Table------------------------------------
        //---insert a title into the database---

        public long insertCreditcard(int i, String j, String k, String l, String date) 
        {
            ContentValues creditValues = new ContentValues();
            creditValues.put(KEY_CCID, i);
            creditValues.put(KEY_CCUNAME, j);
            creditValues.put(KEY_CCNO, k);
            creditValues.put(KEY_CVV, l);
            creditValues.put(EXP_DATE, date);
            return db.insert(CREDITCARDS_TABLE, null, creditValues);
        }


      //---opens the database---
        public DBAdapter open() throws SQLException 
        {
            db = DBHelper.getWritableDatabase();
            return this;
        }

        //---closes the database---    
        public void close() 
        {
            DBHelper.close();
        }

        //---insert a title into the database---
        public long insertTitle(String name, String username, String password) 
        {
            ContentValues initialValues = new ContentValues();
            initialValues.put(KEY_Name, name);
            initialValues.put(KEY_Username, username);
            initialValues.put(KEY_Password, password);
            return db.insert(DATABASE_TABLE, null, initialValues);
        }

        //---deletes a particular title---
        public boolean deleteTitle(long rowId) 
        {
            return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
        }

        //---retrieves all the titles---
        public Cursor getAllTitles() 
        {
            return db.query(DATABASE_TABLE, new String[] {
                    KEY_ROWID, 
                    KEY_Name,
                    KEY_Username,
                    KEY_Password}, 
                    null, 
                    null, 
                    null, 
                    null, 
                    null);
        }

        //---retrieves a particular title---
        public Cursor getTitle(long rowId) throws SQLException 
        {
            Cursor mCursor =
                    db.query(true, DATABASE_TABLE, new String[] {
                            KEY_ROWID,
                            KEY_Name, 
                            KEY_Username,
                            KEY_Password
                            }, 
                            KEY_ROWID + "=" + rowId, 
                            null,
                            null, 
                            null, 
                            null, 
                            null);
            if (mCursor != null) {
                mCursor.moveToFirst();
            }
            return mCursor;
        }

        //---updates a title---
        public boolean updateTitle(long rowId, String name, 
        String username, String password) 
        {
            ContentValues args = new ContentValues();
            args.put(KEY_Name, name);
            args.put(KEY_Username, username);
            args.put(KEY_Password, password);
            return db.update(DATABASE_TABLE, args, 
                             KEY_ROWID + "=" + rowId, null) > 0;
        }
    }

- arun

---

你可以很好地为此设立单独的表，这似乎不是一个问题。为那个表设立单独的函数并调用它们。 - Aman Alam

@Sheikh Aman，您能否澄清一下，当我从dbadapter调用open()方法时，是否会同时打开我创建的两个表格？ - arun

当您调用open()函数时，它会打开数据库。该数据库包含所有表格，因此您可以在数据库中运行查询以获取所有表格的数据。 - Aman Alam

你有收到任何错误吗？ - Subburaj

你什么时候实例化 'DBAdapter' 并且什么时候调用它的 'open' 方法？ - dev.bmax

Answer 1

我猜在CCTABLE_CREATE的创建语句中，在cvvno text not null之后缺少了,：

  private static final String CCTABLE_CREATE =
            "create table Creditcard_Details ( _ccid integer primary key , "
            + "cuname text not null, ccno text not null, " 
            + "cvvno text not null" + "expdate text not null )";//+ "FOREIGN KEY(_ccid) REFERENCES User_Details(_id))";

这应该是：

这是：

  private static final String CCTABLE_CREATE =
            "create table Creditcard_Details ( _ccid integer primary key , "
            + "cuname text not null, ccno text not null, " 
            + "cvvno text not null, " + "expdate text not null )";//+ "FOREIGN KEY(_ccid) REFERENCES User_Details(_id))";

尝试这样做。如果不起作用，我会进一步探究。

- Nilesh Deokar

Answer 2

由于我的评分较低，我无法发表评论，但我可以在评论中回答您的问题：

.getWritableDatabase();函数提供了一个可写的数据库，正如其名称所示。 现在，数据库中的所有表都已准备好使用。

例如：

public Cursor getStuff(String string) {
    return db.query(true, TABLE_1, new String[] { KEY_COLUMN1, KEY_COLUMN1,
            KEY_COLUMN1 }, KEY_ID + " =  ?", new String[] { string },
            null, null, null, null);
}

我定义的所有大写字母字符串常量都是在我的类中 - 因为我懒得打。如果您想查询其他表，请将 TABLE_1 替换为所需的表。

- Johnnycube