Android SQLiteDatabase列不存在

因此，我正在使用SQLite爲我的Android應用程序創建數據庫，出於某種原因，它認爲我的列「START_DATE_COLUMN」不存在（我的日誌語句爲列索引返回-1）。這很奇怪，因爲當我在SQLite瀏覽器中查看.db文件時，列中有所有我添加的條目。Android SQLiteDatabase列不存在

下面是我的DatabaseHelper類的代碼：

import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.provider.BaseColumns; 
import android.util.Log; 

public class DatabaseHelper extends SQLiteOpenHelper implements BaseColumns { 

public static final int DATABASE_VERSION = 3; 
public static final String DATABASE_NAME = "JobEntries.db"; 
public static final String TABLE_NAME = "jobs"; 
public static final String NAME_COLUMN = "name"; 
public static final String START_DATE_COLUMN = "startDate"; 

private static final String SQL_CREATE_ENTRIES = "CREATE TABLE " + TABLE_NAME + " " + 
     "(" + _ID + " INTEGER PRIMARY KEY, " 
     + NAME_COLUMN 
     + " TEXT, " 
     + START_DATE_COLUMN 
     + " TEXT)"; 
private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS " + TABLE_NAME; 

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

@Override 
public void onCreate(SQLiteDatabase db) { 
    db.execSQL(SQL_CREATE_ENTRIES); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    db.execSQL(SQL_DELETE_ENTRIES); 
    onCreate(db); 
} 

public boolean insertJob(JobEntry job){ 
    SQLiteDatabase db = this.getWritableDatabase(); 
    ContentValues contentValues = new ContentValues(); 
    contentValues.put(this.NAME_COLUMN, job.getClientName()); 
    contentValues.put(this.START_DATE_COLUMN, job.getStartDate()); 
    db.insert(this.TABLE_NAME,null,contentValues); 
    return true; 
} 

public Cursor getDataByDate(String startDate){ 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor result = db.rawQuery("SELECT " + NAME_COLUMN + " FROM " +TABLE_NAME+" WHERE " +START_DATE_COLUMN+ " =" +startDate+"",null); 
    result.moveToFirst(); 
    Log.d("Column Index ", Integer.toString(result.getColumnIndex(START_DATE_COLUMN))); 
    return result; 
} 
}

來源

2017-10-15 kinso009

startDate是一個文本

試圖將一個單引號「添加到您的查詢whereArgs並添加START_DATE_COLUMN您選擇柱等：

Cursor result = db.rawQuery("SELECT " + NAME_COLUMN + ", " + START_DATE_COLUMN + " FROM " +TABLE_NAME+" WHERE " +START_DATE_COLUMN+ " = '" +startDate+ "' ",null);

或

Cursor result = db.query(TABLE_NAME, new String[] { NAME_COLUMN, START_DATE_COLUMN }, START_DATE_COLUMN + " = ? ", new String[] { startDate }, null, null, null);

來源

2017-10-16 02:55:15 Jerrol

-1

這是你所引用的日誌語句？

Log.d("Column Index ", Integer.toString(result.getColumnIndex(START_DATE_COLUMN)));

如果是這樣，則返回-1，因爲你是不是在你前面的方法建立在SELECT語句中選擇START_DATE_COLUMN。這將是修改的SELECT語句的一種方式，以包括柱：

Cursor result = db.rawQuery("SELECT " + NAME_COLUMN + ", " + START_DATE_COLUMN + " FROM " +TABLE_NAME+" WHERE " +START_DATE_COLUMN+ " =" +startDate+"",null);

來源

2017-10-15 22:21:01

-1

這個db.rawQuery("SELECT " + NAME_COLUMN + " FROM " +TABLE_NAME+" WHERE " +START_DATE_COLUMN+ " =" +startDate+"",null);會產生這樣的結果。你得到-1，因爲你只能從NAME_COLUMN查詢數據，

+-------------------+ 
|  name  | 
+-------------------+ 
| Android Developer | 
| Python Developer | 
| Django Developer | 
+-------------------+

如果您還希望包括START_DATE_COLUMN，那麼我們就可以查詢更改爲"SELECT * FROM " +TABLE_NAME+" WHERE " + START_DATE_COLUMN + " =" +startDate+""或"SELECT " + NAME_COLUMN + ", " + START_DATE_COLUMN + " FROM " +TABLE_NAME+" WHERE " +START_DATE_COLUMN+ " =" +startDate+""這將產生：

+-------------------+--------------+ 
|  Name  | startDate | 
+-------------------+--------------+ 
| Android Developer | October 16th | 
| Python Developer | October 17th | 
| Django Developer | October 18th | 
+-------------------+--------------+

現在， Integer.toString(result.getColumnIndex(START_DATE_COLUMN))不會返回-1。

來源

2017-10-16 03:23:48

Android SQLiteDatabase列不存在

回答

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