android.database.sqlite.SQLiteException : no such column : id (code 1) while compiling : s

Question

单击“插入”按钮时发现以下错误

Error Found :android.database.sqlite.SQLiteException: no such column : id (code 1) while compiling : select id,student_name, student_rollno FROM studentTable WHERE idrh

发现错误:android.database.sqlite.SQLiteException:编译时没有这样的列:id(代码 1):从 studentTable WHERE idrh 选择 id，student_name，student_rollno

注意:这里rh是我输入的id

编码

数据库助手.java

    package com.example.a;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;


public class DbActivity  {
public static final String KEY_ID = "id";
public static final String KEY_NAME = "student_name";
public static final String KEY_ROLLNO = "student_rollno";


private static final String DATABASE_NAME= "Studentdb";
private static final int DATABASE_VERSION  = 1;
private static final String  DATABASE_TABLE = "studentTable";

private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;

class DbHelper extends SQLiteOpenHelper {

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        // TODO Auto-generated method stub
    /*  db.execSQL("CREATE TABLE IF NOT EXISTS " + DATABASE_TABLE + " ( " + 
        KEY_ID + " TEXT PRIMARY KEY , " +
        KEY_NAME + " TEXT NOT NULL , " + 
        KEY_ROLLNO + " TEXT NOT NULL );" 
    */
        db.execSQL("CREATE TABLE if not exists database_table (id TEXT PRIMARY KEY ,"
                + "student_name"
                + " TEXT ,"
                + "student_rollno"
                + " TEXT);");

            }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(db);
    }

}


public DbActivity(Context c) {
ourContext = c;
}

public DbActivity open() throws SQLException{
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close() {
    ourHelper.close();
}

public void createEntry(String id, String name, String rollno) {
    // TODO Auto-generated method stub
    ContentValues cv = new ContentValues();
    cv.put(KEY_ID, id);
    cv.put(KEY_NAME, name);
    cv.put(KEY_ROLLNO, rollno);
    ourDatabase.insert(DATABASE_TABLE, null, cv);
}


public String getData() throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    String result = "";

    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null,null);
    int id = c.getColumnIndex(KEY_ID);
    int name = c.getColumnIndex(KEY_NAME);
    int rollno = c.getColumnIndex(KEY_ROLLNO);

    for(c.moveToFirst();!c.isAfterLast();c.moveToNext());
    {
        result = result + c.getColumnName(id) + "" + c.getColumnName(name) + "" + c.getColumnName(rollno) + "/n";

    }
    return result;
}



public String getName(String s) throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ID + "" + s, null, null, null, null);
    if(c!=null)
    {
        c.moveToFirst();
        String name = c.getString(1);
        return name; 
    }
    return null;

}

public String getRollno(String s) throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ID + "" + s, null, null, null, null);
    if(c!=null)
    {
        c.moveToFirst();
        String rollno = c.getString(2);
        return rollno;
    }
    return null;

}

public void updateEntry (String id1, String name, String rollno) throws SQLException {
ContentValues cvUpdate = new ContentValues();
cvUpdate.put(KEY_ID, id1);
cvUpdate.put(KEY_NAME, name);
cvUpdate.put(KEY_ROLLNO, rollno);
ourDatabase.update(DATABASE_TABLE, cvUpdate, KEY_ID + "=" + id1 , null);
}

public void deleteEntry(String id) throws SQLException {

    ourDatabase.delete(DATABASE_TABLE, KEY_ID + "=" + id , null);
}

主 Activity .java

package com.example.a;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;


public class DbActivity  {
public static final String KEY_ID = "id";
public static final String KEY_NAME = "student_name";
public static final String KEY_ROLLNO = "student_rollno";


private static final String DATABASE_NAME= "Studentdb";
private static final int DATABASE_VERSION  = 1;
private static final String  DATABASE_TABLE = "studentTable";

private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;

class DbHelper extends SQLiteOpenHelper {

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        // TODO Auto-generated method stub
    /*  db.execSQL("CREATE TABLE IF NOT EXISTS " + DATABASE_TABLE + " ( " + 
        KEY_ID + " TEXT PRIMARY KEY , " +
        KEY_NAME + " TEXT NOT NULL , " + 
        KEY_ROLLNO + " TEXT NOT NULL );" 
    */
        db.execSQL("CREATE TABLE if not exists database_table (id TEXT PRIMARY KEY ,"
                + "student_name"
                + " TEXT ,"
                + "student_rollno"
                + " TEXT);");

            }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(db);
    }

}


public DbActivity(Context c) {
ourContext = c;
}

public DbActivity open() throws SQLException{
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close() {
    ourHelper.close();
}

public void createEntry(String id, String name, String rollno) {
    // TODO Auto-generated method stub
    ContentValues cv = new ContentValues();
    cv.put(KEY_ID, id);
    cv.put(KEY_NAME, name);
    cv.put(KEY_ROLLNO, rollno);
    ourDatabase.insert(DATABASE_TABLE, null, cv);
}


public String getData() throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    String result = "";

    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null,null);
    int id = c.getColumnIndex(KEY_ID);
    int name = c.getColumnIndex(KEY_NAME);
    int rollno = c.getColumnIndex(KEY_ROLLNO);

    for(c.moveToFirst();!c.isAfterLast();c.moveToNext());
    {
        result = result + c.getColumnName(id) + "" + c.getColumnName(name) + "" + c.getColumnName(rollno) + "/n";

    }
    return result;
}



public String getName(String s) throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ID + "" + s, null, null, null, null);
    if(c!=null)
    {
        c.moveToFirst();
        String name = c.getString(1);
        return name; 
    }
    return null;

}

public String getRollno(String s) throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ID + "" + s, null, null, null, null);
    if(c!=null)
    {
        c.moveToFirst();
        String rollno = c.getString(2);
        return rollno;
    }
    return null;

}

public void updateEntry (String id1, String name, String rollno) throws SQLException {
ContentValues cvUpdate = new ContentValues();
cvUpdate.put(KEY_ID, id1);
cvUpdate.put(KEY_NAME, name);
cvUpdate.put(KEY_ROLLNO, rollno);
ourDatabase.update(DATABASE_TABLE, cvUpdate, KEY_ID + "=" + id1 , null);
}

public void deleteEntry(String id) throws SQLException {

    ourDatabase.delete(DATABASE_TABLE, KEY_ID + "=" + id , null);
}
}

}

activity_main.xml 文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<EditText
    android:id="@+id/etSQLName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dp"
    android:ems="10"
    android:hint="Enter Name" >

    <requestFocus />
</EditText>

<Button
    android:id="@+id/bSQLInsert"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/bSQLMain"
    android:layout_marginLeft="17dp"
    android:layout_marginTop="38dp"
    android:text="Insert" />

<Button
    android:id="@+id/bSQLUpdate"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/bSQLInsert"
    android:layout_alignBottom="@+id/bSQLInsert"
    android:layout_toRightOf="@+id/bSQLInsert"
    android:text="update" />

<Button
    android:id="@+id/bSQLView"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/bSQLUpdate"
    android:layout_alignBottom="@+id/bSQLUpdate"
    android:layout_toRightOf="@+id/bSQLUpdate"
    android:text="view" />

<Button
    android:id="@+id/bSQLDelete"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/bSQLView"
    android:layout_toRightOf="@+id/bSQLView"
    android:text="delete" />

<Button
    android:id="@+id/bSQLBack"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/bSQLUpdate"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="18dp"
    android:text="back" />

<Button
    android:id="@+id/bSQLMain"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/etSQLRollno"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="83dp"
    android:text="Next" />

<EditText
    android:id="@+id/etSQLRollno"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/etSQLName"
    android:layout_below="@+id/etSQLName"
    android:ems="10"
    android:hint="Enter Rollno"
   />

<EditText
    android:id="@+id/etSQLId"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/etSQLRollno"
    android:layout_below="@+id/etSQLRollno"
    android:layout_marginTop="20dp"
    android:ems="10"
    android:hint="enter ID"
    />

2> 问题 - 如何删除已由 AVD 或虚拟设备创建的表

Answer 1

希望这对你有帮助:

替换这一行:

public static final String KEY_ID = "id";

由

public static final String KEY_ID = "_id";

编辑://改变这个方法

public String getName(String s) throws SQLException {
    // TODO Auto-generated method stub
    String[] columns = new String[]{KEY_ID,KEY_NAME,KEY_ROLLNO};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ID + "=" + s, null, null, null, null);// change this line in this method
    if(c!=null)
    {
        c.moveToFirst();
        String name = c.getString(1);
        return name; 
    }
    return null;

}