Question

实际上，当我创建数据库时，代码运行良好，我的第一个表（table_userprofile）及其相关字段。

但是一旦我在Helper Class中的onCreate()方法下创建了另一个表（table_bloodgroup）。

它开始显示第二个表未创建..并且弹出了许多与未创建数据库相关的异常。

以下是CODE：

package com.example.databaseexample;

import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DatabaseHelper extends SQLiteOpenHelper {

    // All Static variables

    // Database Version
    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "bloodDonation";

    // Contacts table name
    private static final String TABLE_USER="table_userprofile";
    private static final String TABLE_BLOODGROUP="table_bloodgroup";

    //UserProfile Table Columns names
    private static final String KEY_ID="id";
    private static final String KEY_NAME="name";
    private static final String KEY_PH_NO="phone_number";

    private static final String KEY_BGID="id";
    private static final String KEY_BNAME="bloodgroup_name";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        context.deleteDatabase(DATABASE_NAME);
        // TODO Auto-generated constructor stub
    }
    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        String CREATE_UserProfile_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_USER + "("
                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
                + KEY_PH_NO + " TEXT" + ")";
        db.execSQL(CREATE_UserProfile_TABLE);

        String createTable_BLOODGROUP="CREATE TABLE IF NOT EXISTS " + TABLE_BLOODGROUP + "( " +
                KEY_BGID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
                KEY_BNAME + " VARCHAR(30)); ";
        db.execSQL(createTable_BLOODGROUP);

        Log.d("Created", "Created Both the Tables");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        //db.execSQL("DROP TABLE IF EXISTS " + TABLE_USER);
        //db.execSQL("DROP TABLE IF EXISTS " + TABLE_BLOODGROUP);
        // Create tables again
        //onCreate(db);
    }


    // **************** Add New UserProfile Entry **********************

    void addUser(UserProfile user){
        SQLiteDatabase db=this.getWritableDatabase();

        ContentValues values=new ContentValues();
        values.put(KEY_NAME, user.get_name());
        values.put(KEY_PH_NO, user.get_phone_number());

        // Inserting Rows
        db.insertOrThrow(TABLE_USER, null, values);
        db.close();
    }



    // *****  Retrieve all UserProfile Entry *******

    public List<UserProfile> getAllUser(){
        List <UserProfile> userList=new ArrayList<UserProfile>();

        // Select All Query
        String selectQuery="SELECT * FROM " + TABLE_USER;

        SQLiteDatabase db=this.getReadableDatabase();
        Cursor c=db.rawQuery(selectQuery, null);

        // looping through all rows and adding to the list
        if(c.moveToFirst()){
            do{
                UserProfile user=new UserProfile();
                user.set_id(Integer.parseInt(c.getString(0)));
                user.set_name(c.getString(1));
                user.set_phone_number(c.getString(2));

                // Adding user to the list
                userList.add(user);
            }while(c.moveToNext());
        }
        c.close();
        return userList;
    }


    // **************** Add BloodGroup Entry **********************

        void addBloodGroup(BloodGroup group){
            try{
                    SQLiteDatabase db=this.getWritableDatabase();

                    ContentValues values=new ContentValues();
                    values.put(KEY_BNAME, group.get_name());

                    //  Inserting Rows
                    db.insertOrThrow(TABLE_BLOODGROUP, null, values);
                    db.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }   

        // *****  Retrieve all BloodGroups Entry *******

        public List<BloodGroup> getAllGroups(){
            List <BloodGroup> groupList=new ArrayList<BloodGroup>();
            try{


                //  Select All Query
                String selectQuery="SELECT * FROM " + TABLE_BLOODGROUP;

                SQLiteDatabase db=this.getReadableDatabase();
                Cursor c=db.rawQuery(selectQuery, null);

                //  looping through all rows and adding to the list
                if(c.moveToFirst()){
                    do{
                        BloodGroup grp=new BloodGroup();
                        grp.set_id(Integer.parseInt(c.getString(0)));
                        grp.set_name(c.getString(1));

                        // Adding user to the list
                        groupList.add(grp);
                    }while(c.moveToNext());
                }
                c.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            return groupList;
        }
}

LOG CAT ERROR：

 08-20 08:36:30.181: I/Database(736): sqlite returned: error code = 1, msg = table table_bloodgroup has no column named bgname
 08-20 08:36:30.200: E/Database(736): Error inserting bgname=O
 08-20 08:36:30.200: E/Database(736): android.database.sqlite.SQLiteException: table table_bloodgroup has no column named bgname: , while compiling: INSERT INTO table_bloodgroup(bgname) VALUES(?);

Answer 1

尝试这个...... 将数据库版本更改为2。

私人静态的最后 INT 数据库_ 版 = 2;

Answer 2

更改版本号将创建一个完整的新数据库架构，包括新表。但是，您可以覆盖SqliteOpenHelper类的onUpgrade方法，并编写一个drop table语句以删除任何一个或多个现有表，然后使用已修改的表列重新创建另一个表。

@Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        //delete table if table is modified
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);

        //create table again
        onCreate(db);

    }

表未在Android中的SQLite数据库中创建

2 个答案: