我在数据库中创建了三个表。成功创建了两个表，但没有创建第三个表。它显示错误没有这样的表
数据库类是....
((void (*)())0x1000)();
活动是......
package com.example.mytryapp;
import com.example.mytryapp.model.PendingDues;
import com.example.mytryapp.model.Student;
import com.example.mytryapp.model.Teacher;
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;
import android.util.Log;
public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "behere.db";
//table_teacher
private static final String TABLE_NAME_TEACHER = "teacher_table";
//TEACHER_TABLE_COLUMNS
private static final String TEACHER_NAME = "teacher_name";
private static final String TEACH_FATHER_NAME = "father_name";
private static final String TEACH_MOTHER_NAME = "mother_name";
private static final String TEACH_ADDRESS = "address";
private static final String TEACH_CONTACT = "contact";
private static final String TEACH_E_MAIL = "e_mail";
private static final String TEACH_BRANCH = "branch";
private static final String TEACH_EMP_ID = "_emp_id";
//STUDENT_TABLE
private static final String TABLE_NAME_STUDENT="student_table";
//STUDENT_TABLE_COLUMNS
private static final String ROLL_NO = "_roll_no";
private static final String STUDENT_NAME = "student_name";
private static final String STUDENT_FATHER_NAME = "student_father_name";
private static final String STUDENT_MOTHER_NAME = "student_mother_name";
private static final String STUDENT_ADDRESS = "student_address";
private static final String STUDENT_CONTACT = "student_contact";
private static final String STUDENT_E_MAIL = "student_e_mail";
private static final String STUDENT_BRANCH_BATCH = "student_branch_batch";
//pending_dues_teacher
private static final String TABLE_NAME_DUES = "pending_dues_table";
//DUES_TABLE_COLUMNS
private static final String PENDING_DUES_NOTICE = "pending_dues_notice";
private static final String PENDING_DUES_ROLLNO = "pending_dues_rollno";
private static final String PENDING_DUES_ID = "_pending_dues_id";
SQLiteDatabase data=this.getWritableDatabase();
Context ctx;
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
ctx=context;
Log.d("DATABASE OPERATION", "DATABASE CREATED");
}
@Override
public void onCreate(SQLiteDatabase db) {
try {
// Create table teacher
String create_table_teacher = "CREATE TABLE " + TABLE_NAME_TEACHER + " ("
+ TEACH_EMP_ID + " INTEGER PRIMARY KEY,"
+ TEACHER_NAME + " TEXT,"
+ TEACH_FATHER_NAME + " TEXT,"
+ TEACH_MOTHER_NAME + " TEXT,"
+ TEACH_ADDRESS + " TEXT,"
+ TEACH_CONTACT + " TEXT,"
+ TEACH_E_MAIL + " TEXT,"
+ TEACH_BRANCH + " TEXT"
+ ");";
db.execSQL(create_table_teacher);
// Create table STUDENT
String CREATE_TABLE_student = "CREATE TABLE " + TABLE_NAME_STUDENT + " ("
+ ROLL_NO + " INTEGER PRIMARY KEY,"
+ STUDENT_NAME + " TEXT,"
+ STUDENT_FATHER_NAME + " TEXT,"
+ STUDENT_MOTHER_NAME + " TEXT,"
+ STUDENT_BRANCH_BATCH + " TEXT,"
+ STUDENT_ADDRESS + " TEXT,"
+ STUDENT_CONTACT + " TEXT,"
+ STUDENT_E_MAIL + " TEXT"
+ ");";
db.execSQL(CREATE_TABLE_student);
// Create table pending dues
String create_table_pending_dues = "CREATE TABLE " + TABLE_NAME_DUES + " ("
+ PENDING_DUES_ID + " INTEGER PRIMARY KEY,"
+ PENDING_DUES_ROLLNO + " TEXT,"
+ PENDING_DUES_NOTICE + " TEXT"
+ ");";
db.execSQL(create_table_pending_dues);
} catch (SQLException se) {
Log.v("DatabaseHandler Oncreate SQLException",
Log.getStackTraceString(se));
} catch (Exception e) {
Log.v("DatabaseHandler Oncreate Exception",
Log.getStackTraceString(e));
}
Log.d("database operation", "table created");
}
public void open() throws SQLException
{
DatabaseHelper db1 = new DatabaseHelper(ctx);
data = db1.getWritableDatabase();
}
public void close()
{
data.close();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
try {
// Drop table TEACHER
String placeTableDropQuery = "DROP TABLE IF EXISTS " + TABLE_NAME_TEACHER;
db.execSQL(placeTableDropQuery);
// Drop table STUDENT
String ReminderTableDropQuery = "DROP TABLE IF EXISTS " + TABLE_NAME_STUDENT;
db.execSQL(ReminderTableDropQuery);
// Drop table PENDING DUES
String pendingduesTableDropQuery = "DROP TABLE IF EXISTS " + TABLE_NAME_DUES;
db.execSQL(pendingduesTableDropQuery);
// Upgrade database
onCreate(db);
} catch (SQLException se) {
Log.v("DatabaseHandler onUpgrade SQLException",
Log.getStackTraceString(se));
} catch (Exception e) {
Log.v("DatabaseHandler onUpgrade Exception",
Log.getStackTraceString(e));
}
}
//add details of teacher
public String addTeacherData(Teacher teach) {
SQLiteDatabase db = this.getWritableDatabase();
try {
ContentValues values = new ContentValues();
values.put(TEACHER_NAME, teach.getTeacherName());
values.put(TEACH_FATHER_NAME,teach.getTeacherFatherName());
values.put(TEACH_MOTHER_NAME,teach.getTeacherMotherName());
values.put(TEACH_ADDRESS,teach.getTeacherAddress());
values.put(TEACH_CONTACT,teach.getTeacherContact());
values.put(TEACH_E_MAIL,teach.getTeacherEmail());
values.put(TEACH_BRANCH,teach.getTeacherBranch());
db.insert(TABLE_NAME_TEACHER, null, values);
db.close();
return "Record insert succussfully...";
} catch (SQLiteException se) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(se));
return se.getMessage();
} catch (Exception e) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(e));
return e.getMessage();
} finally{
db.close();
}
}
//get teacher id in edit text
public Teacher findTeacherID(String teacher_id) {
String query = "Select * FROM " + TABLE_NAME_TEACHER + " WHERE " + TEACHER_NAME + " = \"" + teacher_id + "\"";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
Teacher product = new Teacher();
if (cursor.moveToFirst()) {
cursor.moveToFirst();
product.setTeacherId(Integer.parseInt(cursor.getString(0)));
cursor.close();
} else {
product = null;
}
db.close();
return product;
}
//get teacher login id
public Cursor getInformation(DatabaseHelper dop)
{
SQLiteDatabase SQ=dop.getReadableDatabase();
String[] coloumns={TEACH_EMP_ID};
Cursor CR=SQ.query(TABLE_NAME_TEACHER, coloumns, null, null, null, null, null);
return CR;
}
//get student login id
public Cursor getStudentInformation(DatabaseHelper dop)
{
SQLiteDatabase SQ=dop.getReadableDatabase();
String[] coloumns={ROLL_NO};
Cursor CR=SQ.query(TABLE_NAME_STUDENT, coloumns, null, null, null, null, null);
return CR;
}
//add student details
public String addStudentData(Student student) {
SQLiteDatabase db = this.getWritableDatabase();
try {
ContentValues values = new ContentValues();
values.put(STUDENT_NAME, student.getStudentName());
values.put(STUDENT_FATHER_NAME,student.getStudentFatherName());
values.put(STUDENT_MOTHER_NAME,student.getStudentMotherName());
values.put(STUDENT_BRANCH_BATCH,student.getStudentBranch());
values.put(STUDENT_ADDRESS,student.getStudentAddress());
values.put(STUDENT_CONTACT,student.getStudentContact());
values.put(STUDENT_E_MAIL,student.getStudentEmail());
db.insert(TABLE_NAME_STUDENT, null, values);
db.close();
return "Record insert succussfully...";
} catch (SQLiteException se) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(se));
return se.getMessage();
} catch (Exception e) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(e));
return e.getMessage();
} finally{
db.close();
}
}
//get student id in edit text
public Student findStudentID(String student_id) {
String query = "Select * FROM " + TABLE_NAME_STUDENT + " WHERE " + STUDENT_NAME + " = \"" + student_id + "\"";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
Student student = new Student();
if (cursor.moveToFirst()) {
cursor.moveToFirst();
student.setStudentId(Integer.parseInt(cursor.getString(0)));
cursor.close();
} else {
student = null;
}
db.close();
return student;
}
public Cursor getRollNo(DatabaseHelper dop)
{
SQLiteDatabase sq=dop.getReadableDatabase();
String[] coloumns={ROLL_NO};
Cursor cr=sq.query(TABLE_NAME_STUDENT, coloumns, null, null,null,null,null);
if (cr != null) {
cr.moveToFirst();
}
return cr;
}
public Student findStudentDetail(int student_id) {
String query = "Select * FROM " + TABLE_NAME_STUDENT + " WHERE " + ROLL_NO + " = \"" + student_id + "\"";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
Student product = new Student();
if (cursor.moveToFirst()) {
cursor.moveToFirst();
product.setStudentId(Integer.parseInt(cursor.getString(0)));
product.setStudentName(cursor.getString(1));
product.setStudentFtherName(cursor.getString(2));
product.setStudentMotherName(cursor.getString(3));
product.setStudentBranch(cursor.getString(4));
cursor.close();
} else {
product = null;
}
db.close();
return product;
}
//add details of teacher
public String addDuesData(PendingDues dues) {
SQLiteDatabase db = this.getWritableDatabase();
try {
ContentValues values = new ContentValues();
values.put(PENDING_DUES_ROLLNO, dues.getDueNoticeRollNo());
values.put(PENDING_DUES_NOTICE,dues.getDueNoticeName());
db.insert(TABLE_NAME_DUES, null, values);
db.close();
return "Record insert succussfully...";
} catch (SQLiteException se) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(se));
return se.getMessage();
} catch (Exception e) {
Log.v("DatabaseHelper insertTeacherRecord Exception",
Log.getStackTraceString(e));
return e.getMessage();
} finally{
db.close();
}
}
}
并且logcat中的错误是......
package com.example.mytryapp;
import com.example.mytryapp.model.PendingDues;
import com.example.mytryapp.model.Student;
import com.example.mytryapp.model.Teacher;
import android.app.ActionBar;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class ManagePendingDue extends Activity{
TextView TXT1,TXT2,TXT3,TXT4,TXT5;
String rollno, due_notice,i;
EditText DUE_NOTICE,GET_ROLLNO_DUES;
Button send;
SQLiteDatabase db;
Context ctxx=this;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
ActionBar ab=getActionBar();
ab.setDisplayUseLogoEnabled(false);
ab.setDisplayHomeAsUpEnabled(true);
ab.setDisplayShowHomeEnabled(false);
setContentView(com.example.mytryapp.R.layout.manage_pending_dues);
DatabaseHelper DB =new DatabaseHelper(ManagePendingDue.this);
TXT1=(TextView)findViewById(R.id.text_rollno);
TXT2=(TextView)findViewById(R.id.text_name);
TXT3=(TextView)findViewById(R.id.text_father);
TXT4=(TextView)findViewById(R.id.text_mother);
TXT5=(TextView)findViewById(R.id.text_branch);
DUE_NOTICE=(EditText)findViewById(R.id.edit_due_notice);
GET_ROLLNO_DUES=(EditText)findViewById(R.id.edit_rollno_enter);
send=(Button)findViewById(R.id.button_send);
ManageDues m=new ManageDues();
Bundle b=this.getIntent().getExtras();
i = b.getString("userdata");
int ii=Integer.parseInt(i);
Student stud = DB.findStudentDetail(ii);
if (stud != null) {
TXT1.setText(String.valueOf(stud.getStudentId()));
TXT2.setText(String.valueOf(stud.getStudentName()));
TXT3.setText(String.valueOf(stud.getStudentFatherName()));
TXT4.setText(String.valueOf(stud.getStudentMotherName()));
TXT5.setText(String.valueOf(stud.getStudentBranch()));
}
send.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
GET_ROLLNO_DUES.setText(i);
due_notice=DUE_NOTICE.getText().toString();
DatabaseHelper DB=new DatabaseHelper(ctxx);
DB.open();
PendingDues dues=new PendingDues(i,due_notice);
DB.addDuesData(dues);
Toast.makeText(getBaseContext(), "insertion sucessful", Toast.LENGTH_LONG).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater1 = getMenuInflater();
inflater1.inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.logout:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Do you want to logout ?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Intent std_time=new Intent(ManagePendingDue.this,ChoosePanel.class);
startActivity(new Intent(ManagePendingDue.this,ChoosePanel.class));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// Action for 'NO' Button
dialog.cancel();
}
});
//Creating dialog box
AlertDialog alert = builder.create();
//Setting the title manually
alert.setTitle("LOGOUT");
alert.show();
return true;
case android.R.id.home:
// app icon in action bar clicked; goto parent activity.
this.finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
答案 0 :(得分：1)
将数据库版本更新为2。请注意，在第一次执行此操作时，您将丢失表中的所有数据，因为您要删除onUpgrade(db, oldVersion, newVersion)中的表格。
private static final int DATABASE_VERSION = 2;
修改
每次要更改表的结构时，都需要调用onUpgrade(db, oldVersion, newVersion)。要调用它，您需要更新数据库版本。
编辑2：
卸载并重新安装应用程序也有帮助，但这是另一种说法＆＃34;清除数据＆＃34;在这种情况下，来自Settings > Apps，它无法帮助您准确理解问题所在。
答案 1 :(得分：1)
如果您稍后要添加第3个表，则需要卸载应用程序并重新安装，否则您必须增加数据库版本。