Question

我正在尝试在SQLite数据库（Android）中增加一个值，但是我得到了一个致命的错误：“没有这样的表格＆＃39;在logcat和应用程序粉碎。但是该表存在于数据库中。我的代码可能有问题吗？任何帮助将不胜感激。这是我的更新代码和logcat输出。

a）更新代码

public void tupdateDaysLeft(){
    if (daysLeftCur == null) {
        daysLeftCur = findDaysLeft();
    }

    if (daysLeftCur.moveToFirst()) {
        int columnIndex = daysLeftCursor.getColumnIndex(MsDbAdapter.COL_DAYSLEFT);
        int daysToDel = daysLeftCur.getInt(columnIndex);

    //  int stt = daysToDel;
    //  daysle  = stt;

    mDb.execSQL("UPDATE "+TABLE_PRE+
                " SET "+COL_DAYSLEFT+" = "+COL_DAYSLEFT+" - 1"+
                " WHERE "+COL_ID+" = ?",
                new Object[] { columnIndex });
    }
}

b） - i Logcat输出1

07-16 23:43:36.938: E/SQLiteLog(20992): (1) no such table: TABLE_PRE
07-16 23:43:36.948: E/AndroidRuntime(20992): FATAL EXCEPTION: main
07-16 23:43:36.948: E/AndroidRuntime(20992): android.database.sqlite.SQLiteException: no such table: TABLE_PRE (code 1): , while compiling: update 

TABLE_PRE set COL_DAYSLEFT = COL_DAYSLEFT + 1 where COL_ID = ?
07-16 23:43:36.948: E/AndroidRuntime(20992):    at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
07-16 23:43:36.948: E/AndroidRuntime(20992):    at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1013)
07-16 23:43:36.948: E/AndroidRuntime(20992):    at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:624)
07-16 23:43:36.948: E/AndroidRuntime(20992):    at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
07-16 23:43:36.948: E/AndroidRuntime(20992):    at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)

b） - ii Logcat输出2

01-01 06:31:37.701: E/AndroidRuntime(6357): FATAL EXCEPTION: main
01-01 06:31:37.701: E/AndroidRuntime(6357): java.lang.NullPointerException
01-01 06:31:37.701: E/AndroidRuntime(6357): at com.tembk.mspre.database.MsDbAdapter.tupdateDaysLeft(MsDbAdapter.java:292)
01-01 06:31:37.701: E/AndroidRuntime(6357): at com.tembk.mspre.pre.PreStatus$3.onClick(PreStatus.java:79)

c）表格定义

private static final String TABLE_PRE = "pre";

修改

d）表常量/字段

private static final String TABLE_PRE = "pre";
public static final String COL_ID = "_id";
public static final String COL_BEGINDATE = "begindate";
public static final String COL_TERMEND = "termend";
public static final String COL_DAYSLEFT = "daysleft";
public static final String COL_DATE_TIME = "pre_date_time";

e）表格创建SQL

private static final String PRE_TABLE_CREATE =
    "create table " + TABLE_PRE + " ("
            + COL_ID + " integer primary key autoincrement, "
            + COL_BEGINDATE + " text not null, "
            + COL_TERMEND + " text not null, "
            + COL_DAYSLEFT + " integer not null, "
            + COL_DATE_TIME + " text not null " + ")";

Answer 1

数据库不知道Java代码中有名为TABLE_PRE或daysle的符号;你必须用Java替换它们。

此外，COL_ID可能是ID列的名称，但您需要与所需记录中的值进行比较。

mDb.execSQL("UPDATE "+TABLE_PRE+
            " SET "+COL_DAYSLEFT+" = ?"+
            " WHERE "+COL_ID+" = ?",
            new Object[] { daysle + 1, idOfTheRowToUpdate });

但是，要增加该值，您不需要读取代码中的旧值;你可以直接在SQL中添加：

mDb.execSQL("UPDATE "+TABLE_PRE+
            " SET "+COL_DAYSLEFT+" = "+COL_DAYSLEFT+" + 1"+
            " WHERE "+COL_ID+" = ?",
            new Object[] { idOfTheRowToUpdate });

Answer 2

我通过使用内容值来解决此问题。我在数据库适配器中创建了一个方法，并在我的主要活动中调用它，传递了我需要的值。它看起来很粗糙，但工作正常。

1）数据库适配器更新方法

public boolean updatePreDL(Object mRowId, int daysleft, String preDateTime) {
    ContentValues newValues = new ContentValues();
    newValues.put(COL_DAYSLEFT, daysleft);
    newValues.put(COL_DATE_TIME, preDateTime);
    return mDb.update(TABLE_PRE, newValues, COL_ID + "=" + mRowId, null) > 0;
}

2）按钮单击调用（上面的数据库适配器更新方法）

updateDays.setOnClickListener( new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            mDbHelper.updatePreDL(MsDbAdapter.COL_ID, 
                    daysLeftCur.getInt(daysLeftCur.getColumnIndex(MsDbAdapter.COL_DAYSLEFT))-1, 
                    MsDbAdapter.COL_DATE_TIME);
        }
    });

Answer 3

我认为你应该使用它：

mDb.execSQL("update TABLE_PRE set COL_DAYSLEFT = "+ (daysle + 1) +"  where COL_ID = ?", new Object[] {COL_ID});
}

而不是：

mDb.execSQL("update TABLE_PRE set COL_DAYSLEFT = daysle + 1 where COL_ID = ?", new Object[] {COL_ID});

无法减少Android SQLite DB中的Int值

3 个答案: