Question

我正在使用sqllite进行CRUD操作。但是当我要运行该程序时会显示以下错误。这里我给出了我的databasehelper.java文件＆amp; mainactivity.java文件代码。

这是我的DatabaseHelper.java文件代码。

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {
    public static final String DATABASE_NAME = "Student.db";
    public static final String TABLE_NAME = "Student_Table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "NAME";
    public static final String COL_3 = "SURNAME";
    public static final String COL_4 = "SUBJECT";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE" + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME VARCHAR (20) NOT NULL, SURNAME VARCHAR (20) NOT NULL, SUBJECT VARCHAR (20) NOT NULL)");
    }

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

    public boolean insertData(String name,String surname,String subject){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,subject);
        long result = db.insert(TABLE_NAME,null,contentValues);
        if (result == -1)
            return false;
        else
            return  true;
    }
}

这是我的MainActivity.java文件

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    DatabaseHelper myDb;
    EditText editName,editSurname,editSubject;
    Button btnAddData;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myDb = new DatabaseHelper(this);

        editName = (EditText)findViewById(R.id.editText_Name);
        editSurname = (EditText)findViewById(R.id.editText_SurName);
        editSubject = (EditText)findViewById(R.id.editText_Subject);
        btnAddData = (Button)findViewById(R.id.button_add);
        AddData();
    }

    public void AddData(){
        btnAddData.setOnClickListener(
                new View.OnClickListener(){
                    @Override
                    public void onClick(View v) {
                     boolean isInserted = myDb.insertData(editName.getText().toString(),editSurname.getText().toString(),editSubject.getText().toString());
                        if (isInserted == true)
                            Toast.makeText(MainActivity.this,"Data Inserted",Toast.LENGTH_LONG).show();
                        else
                            Toast.makeText(MainActivity.this,"Data Not Inserted",Toast.LENGTH_LONG).show();
                    }
                }
        );
    }

}

当我要保存数据时，它显示以下消息

“不幸的是，SQlLiteApp已停止......”

Answer 1

从您的日志中： android.database.sqlite.SQLiteException：near“TABLEStudent_Table”：语法错误（代码1）使用以下内容：简而言之，在表格之后和存在之后添加空格

db.execSQL("CREATE TABLE " + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME VARCHAR (20) NOT NULL, SURNAME VARCHAR (20) NOT NULL, SUBJECT VARCHAR (20) NOT NULL);");

升级时：

db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME +";");

Answer 2

您似乎忘记在CREATE TABLE和EXISTS之后添加空格，因此更改

"CREATE TABLE" + TABLE_NAME + "(ID

到

"CREATE TABLE " + TABLE_NAME + " (ID

和

"DROP TABLE IF EXISTS" + TABLE_NAME

到

"DROP TABLE IF EXISTS " + TABLE_NAME

注意：请在重试前卸载应用。

不幸的是，SQlLiteApp已停止

2 个答案: