在 Android sq-lite 数据库中添加新列答案

【问题标题】：Add new column in Android sq-lite database在 Android sq-lite 数据库中添加新列
【发布时间】：2014-06-10 13:24:39
【问题描述】：

我的逻辑是：

只需在单击按钮时将数据插入到 sqlite 数据库中。我已经创建并且工作正常。

我的要求是：

我想在现有的 Sqlite 中再添加一列，所以我手动添加了。

我所做的是我删除了模拟器中的现有表并在我有查询的地方运行我的代码以创建一个新表。在执行代码时，表没有被创建

这是我的代码：

这里 User_Id 是我在 sq-lite DB 中的新列

MainActivity.java

    @Override
    public void onClick(View v) {
            Flag="I";
        if (valid_JobNo != null 
        && valid_Status != null
        && valid_Date_Time != null 
        && valid_User_Id != null

        &&valid_JobNo.length() != 0
        && valid_Status.length() != 0
        && valid_Date_Time.length() != 0
       &&valid_User_Id.length() != 0
        && Flag.length()!=0)
        {

        flagL = "T";
        dbHandler.Add_Tracking(new Tracking(valid_JobNo,
        valid_Status, valid_Date_Time,valid_User_Id,flagL));
        Toast_msg = "Not Connected To Internet.\nData inserted in Sqlite DB successfully";
        Show_Toast(Toast_msg);
        Reset_Text();

        }
        else
        {
            Toast_msg = "Sorry Some Fields are missing.\nPlease Fill up all.";
            Show_Toast(Toast_msg);
        }

数据库处理程序.java

private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "Cargonet";
private static final String TABLE_Tracking = "CargoTracking";

private static final String KEY_ID = "id";
private static final String KEY_JobNo = "JobNo";
private static final String KEY_Status = "Status";
private static final String KEY_User_Id = "User_Id";
private static final String KEY_Flag = "Flag";
private static final String KEY_Date_Time = "Date_Time";
private final ArrayList<Tracking> Tracking_list = new ArrayList<Tracking>();

public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_Tracking_TABLE = "CREATE TABLE " + TABLE_Tracking + "("
    + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_JobNo + " TEXT,"
    + KEY_Status + " TEXT," + KEY_User_Id + " TEXT," + KEY_Date_Time + " TEXT," + KEY_Flag + " TEXT "+ ")";
db.execSQL(CREATE_Tracking_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Tracking);
// Create tables again
onCreate(db);
}

public void Add_Tracking(Tracking Tracking) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_JobNo, Tracking.getJobNo()); // Tracking JobNo
values.put(KEY_Status, Tracking.getStatus());
values.put(KEY_User_Id, Tracking.getUser_Id());
values.put(KEY_Flag, Tracking.getFlag());// Tracking Phone
values.put(KEY_Date_Time, Tracking.getDate_Time());
// Inserting Row
db.insert(TABLE_Tracking, null, values);
db.close(); // Closing database connection
}

Tracking Get_Tracking(int id) {
SQLiteDatabase db = this.getReadableDatabase();

Cursor cursor = db.query(TABLE_Tracking, new String[] { KEY_ID,
    KEY_JobNo, KEY_Status, KEY_Date_Time ,KEY_User_Id, KEY_Flag}, KEY_ID + "=?",
    new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
    cursor.moveToFirst();

Tracking Tracking = new Tracking(Integer.parseInt(cursor.getString(0)),
    cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4),(cursor.getString(5)));
// return Tracking
cursor.close();
db.close();

return Tracking;
}

Tracking Get_TrackingF(String Flag) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_Tracking, new String[] { KEY_ID,
        KEY_JobNo, KEY_Status, KEY_Date_Time ,KEY_User_Id, KEY_Flag}, KEY_Flag + "=?",
        new String[] { String.valueOf(Flag) }, null, null, null, null);
    if (cursor != null)
        cursor.moveToFirst();

    Tracking Tracking = new Tracking(Integer.parseInt(cursor.getString(0)),
        cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4), (cursor.getString(5)));
    // return Tracking
    cursor.close();
    db.close();

    return Tracking;
    }

public ArrayList<Tracking> Get_Tracking() {
try {
    Tracking_list.clear();

    String selectQuery = "SELECT  * FROM " + TABLE_Tracking;

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if (cursor.moveToFirst()) {
    do {
        Tracking Tracking = new Tracking();
        Tracking.setID(Integer.parseInt(cursor.getString(0)));

        Tracking.setJobNo(cursor.getString(1));
        Tracking.setStatus(cursor.getString(2));
        Tracking.setDate_Time(cursor.getString(3));
        Tracking.setUser_Id(cursor.getString(4));
        Tracking.setFlag(cursor.getString(5));
        // Adding Tracking to list
        Tracking_list.add(Tracking);
    } while (cursor.moveToNext());
    }

    cursor.close();
    db.close();
    return Tracking_list;
} catch (Exception e) {
    // TODO: handle exception
    Log.e("all_Tracking", "" + e);
}

return Tracking_list;
}

public int Update_Tracking(Tracking Tracking) {
SQLiteDatabase db = this.getWritableDatabase();

ContentValues values = new ContentValues();
values.put(KEY_JobNo, Tracking.getJobNo());
values.put(KEY_Status, Tracking.getStatus());
values.put(KEY_Date_Time, Tracking.getDate_Time());
values.put(KEY_User_Id, Tracking.getUser_Id());
values.put(KEY_Flag, Tracking.getFlag());

// updating row
return db.update(TABLE_Tracking, values, KEY_ID + " = ?",
    new String[] { String.valueOf(Tracking.getID()) });
}

public void Delete_Tracking(int id) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_Tracking, KEY_ID + " = ?",
    new String[] { String.valueOf(id) });
db.close();
}

public int Get_Total_Tracking(Tracking Tracking) {
String countQuery = "SELECT  * FROM " + TABLE_Tracking;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();

return cursor.getCount();
}

Tracking Get_Flag(String flag) {
SQLiteDatabase db = this.getReadableDatabase();

Cursor cursor = db.query(TABLE_Tracking, new String[] { KEY_ID,
    KEY_JobNo, KEY_Status, KEY_Date_Time ,KEY_User_Id , KEY_Flag}, KEY_Flag + "=?",
    new String[] { String.valueOf(flag) }, null, null, null, null);
if (cursor != null)
    cursor.moveToFirst();

Tracking Tracking = new Tracking(Integer.parseInt(cursor.getString(0)),
    cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4) , (cursor.getString(5)));
    cursor.close();
db.close();

return Tracking;
}
public Cursor getListItem() {
    // TODO Auto-generated method stub
    return null;
}
public void addListItem(ArrayList<String> tracking_data) {
    // TODO Auto-generated method stub
}

}

Tracking.java

public class Tracking {

// private variables
public int _id;
public String _JobNo;
public String _Status;
public String _Flag;
public String _Date_Time;
public String _User_Id;

public Tracking() {
}

public Tracking(int id, String JobNo, String _Status, String _Date_Time,String _User_Id, String _Flag) {
this._id = id;
this._JobNo = JobNo;
this._Status = _Status;
this._Date_Time = _Date_Time;
this._User_Id = _User_Id;
this._Flag = _Flag;
}

public Tracking(String JobNo, String _Status, String _Date_Time,String _User_Id, String _Flag) {
this._JobNo = JobNo;
this._Status = _Status;
this._Date_Time = _Date_Time;
this._User_Id = _User_Id; 
this._Flag = _Flag;
}

public int getID() {
return this._id;
}

public void setID(int id) {
this._id = id;
}

public String getJobNo() {
return this._JobNo;
}

public void setJobNo(String JobNo) {
this._JobNo = JobNo;
}

public String getStatus() {
return this._Status;
}

public void setStatus(String Status) {
this._Status = Status;
}

public String getDate_Time() {
return this._Date_Time;
}

public void setDate_Time(String Date_Time) {
this._Date_Time = Date_Time;
}

public String getUser_Id() {
return this._User_Id;
}

public void setUser_Id(String User_Id) {
this._User_Id = User_Id;
}

public String getFlag() {
    return this._Flag;
    }

public void setFlag(String Flag) {
    this._Flag = Flag;
    }
}

【问题讨论】：

请只发布相关代码。我不会（而且几乎没有人）会阅读所有这些内容。
您的意思是在 Main Activity.java 中？其他两个 java 是我的帖子的 imp。现在我将仅从主要活动先生发布按钮点击..
“相关” 仅表示重要的代码。你怎么知道哪些代码很重要？好吧，删除代码，直到您拥有能够重现您的问题的最少代码。这称为SSCCE。

标签： android sqlite add

【解决方案1】：

不清楚您的问题是什么，或者您想选择哪个选项来添加新列，但通常，要添加新列，您必须检查数据库版本并升级它并添加新列。您可以在 onUpgrade() 中执行此操作：

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

       // If you need to add a new column
        if (newVersion > oldVersion) {
             db.execSQL("ALTER TABLE "+table_name+" ADD COLUMN "+new_column_name + "  INTEGER DEFAULT 0");
         }
     }

除了整数默认值 0，您还可以使用 TEXT NOT NULL 或您想要放入数据库列的任何其他值。

【讨论】：

【解决方案2】：

我浏览了您的大部分代码，但我认为您真正要问的是“如何更新数据库？”

首先您将更改public void onCreate(SQLiteDatabase db) 函数以使用您要添加的新列创建模型数据库结构。然后将DATABASE_VERSION = 1 更改为DATABASE_VERSION = 2。如果新版本大于当前版本，则再次运行删除表和onCreate 函数。

另外，关于public void Add_Tracking(Tracking Tracking) 的旁注将其更改为public void Add_Tracking(Tracking tracking)，并将对变量的所有引用也更改为以小写字母开头。我不确定这是否会导致您的代码出现任何问题，但是当局部变量和类具有相同的名称和格式时，它会令人困惑。

【讨论】：

将 DATABASE_VERSION 更改为等于 2