无法在 Android 上的 SQLite 中创建第二个表

Question

我创建了一个数据库适配器类，它应该创建两个名为 Users_Details 和 Creditcard_Details 的表。然而，当我导出并检查使用 SQLite 浏览器创建的数据库时，我发现只创建了前一个表。我无法理解造成这种情况的原因。 有人可以建议或帮助我调试这个问题吗？

这是数据库适配器的代码：

    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;


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"+ DATABASE_TABLE + " ( " + KEY_ROWID + " integer primary key autoincrement, "
            + KEY_Name + " text not null, " + KEY_Username + " text not null, " 
            + KEY_Password + " text not null);";

        private static final String CCTABLE_CREATE = "create table " + 
        CREDITCARDS_TABLE + " (" + KEY_CCID + 
        " integer primary key autoincrement, " +
        KEY_CCUNAME + "text not null, " + KEY_CCNO + " text not null, " + KEY_CVV + " text not null, " + EXP_DATE + " text not null);";
        /*---------------------Create Credit Card Table -------------------------------*/
      /* private static final String CCTABLE_CREATE =
            "create table"+ CREDITCARDS_TABLE + " ( " + KEY_CCID + " integer primary key , "
            + KEY_CCUNAME + " text not null, " + KEY_CCNO + " ccno text not null, " 
            + KEY_CVV + " text not null, " + EXP_DATE + " 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(); 
            //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 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( 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;
        }
    }

Answer 1

尝试更改 DATABASE_VERSION 数字。我建议这样做是因为您在开发过程中可能有一个表（并且 db_ver 为 1），然后在代码中添加了第二个表，但它没有出现（因此这篇文章）。

或卸载+重新安装即可实现此目的。