如何在android中插入一行新的sqlite表？

Question

我正在为老师开发一个考勤应用程序。我已经创建了数据库，并试图插入一个新的行，但我正在犯错误，我在下面给出了一些必要的代码。数据库创建如下：

String aquery="CREATE TABLE "+ATTENDANCE_TABLE_NAME+" ( COLUMN_DATE TEXT PRIMARY KEY );";
            db.execSQL(aquery);

并将表的更改为：

String aquery="ALTER TABLE "+ATTENDANCE_TABLE_NAME+" ADD COLUMN '"+new_col_name+"' TEXT;";
db.execSQL(aquery);

现在，我将插入一行--新行如下：

ContentValues Values=new ContentValues();
        SQLiteDatabase db=getWritableDatabase();
        // finding all column
        Cursor dbCursor = db.query(ATTENDANCE_TABLE_NAME, null, null, null, null, null, null);
        String[] columnNames = dbCursor.getColumnNames();
        String zero="0";

        for (int i=0;i<columnNames.length;i++)
        {
            // saving values to each specific column
            if(i==0)
                Values.put("COLUMN_DATE", date );
            else
                Values.put(columnNames[i],"'"+zero+"'");
        }
            check = db.insert(ATTENDANCE_TABLE_NAME, null , Values);

但是我发现了一个错误：

05-25 18:52:23.023 19480-19480/com.example.vikas.scannerproject E/SQLiteLog: (1) near "14202": syntax error
05-25 18:52:23.023 19480-19480/com.example.vikas.scannerproject E/SQLiteDatabase: Error inserting COLUMN_DATE=2017-05-25 14202='0'
android.database.sqlite.SQLiteException: near "14202": syntax error (code 1): , while compiling: INSERT INTO CSE_OS_2017_ATTENDANCE(COLUMN_DATE,14202) VALUES (?,?)
                                                                                  at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                                                                                  at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:887)
                                                                                  at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:498)
                                                                                  at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                                                                                  at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
                                                                                  at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
                                                                                  at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
                                                                                  at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
                                                                                  at com.example.vikas.scannerproject.Index_DBHandler.takingAttendance(Index_DBHandler.java:148)
                                                                                  at com.example.vikas.scannerproject.ScanresultActivity.takeAttendance(ScanresultActivity.java:44)
                                                                                  at com.example.vikas.scannerproject.ScanresultActivity.onCreate(ScanresultActivity.java:32)
                                                                                  at android.app.Activity.performCreate(Activity.java:6303)
                                                                                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
                                                                                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2376)
                                                                                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2483)
                                                                                  at android.app.ActivityThread.access$900(ActivityThread.java:153)
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1349)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                  at android.os.Looper.loop(Looper.java:148)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5441)
                                                                                  at java.lang.reflect.Method.invoke(Native Method)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:628)

请帮助我插入新行。

Answer 1

SqLite中的列名不能以0-9开头。将列名更改为"A14202“。

顺便说一下，为每个作业添加一个列可能不是最好的设计。SqLite只允许2000列。

Answer 2

sqlite中的列名应该以字母{a，a}开头。它不应以数值开头。试试这个：

String aquery="ALTER TABLE "+ATTENDANCE_TABLE_NAME+" ADD COLUMN '"+"A"+new_col_name+"' TEXT;";
db.execSQL(aquery);