我正在尝试使用通过数据库浏览器从csv文件创建的数据库。 我尝试卸载并重新安装该应用程序。还升级了数据库版本，仍然发生相同的错误！ 检查了我的数据库路径，以及是否正在创建文件。
DatabaseHelper.java
package com.timespro.bookaseat.Model;
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;
import com.timespro.bookaseat.Students;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String TABLE_NAME1 = "StudentDetails";
private static final int DB_VERSION = 5;
private static String DB_NAME = "data.sqlite";
private String DB_PATH;
private Context mContext;
private SQLiteDatabase mDataBase;
private boolean mNeedUpdate = false;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.mContext = context;
DB_PATH = context.getDatabasePath(DB_NAME).getAbsolutePath();
Log.d("DB_Path",DB_PATH);
}
public void updateDataBase() throws IOException {
if (mNeedUpdate) {
File dbFile = new File(DB_PATH + DB_NAME);
if (dbFile.exists())
dbFile.delete();
copyDataBase();
mNeedUpdate = false;
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}catch(SQLiteException e){
Log.d("DB","DB doesn't exist!");
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transferring bytestream.
* */
private void copyDataBase() throws IOException{
Log.d("DB","Database copied!");
//Open your local db as the input stream
InputStream myInput = mContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the input file to the output file
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
/**
* Creates a empty database on the system and rewrites it with your own database.
**/
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
Log.d("DatabaseHelper","DB already exists!");
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private void copyDBFile() throws IOException {
Log.d("DB","DB File created on phone");
InputStream mInput = mContext.getAssets().open(DB_NAME);
//InputStream mInput = mContext.getResources().openRawResource(getResources().getIdentifier("data","raw", getPackageName()));
OutputStream mOutput = new FileOutputStream(DB_PATH + DB_NAME);
byte[] mBuffer = new byte[1024];
int mLength;
while ((mLength = mInput.read(mBuffer)) > 0)
mOutput.write(mBuffer, 0, mLength);
mOutput.flush();
mOutput.close();
mInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
mDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
Log.d("DB","DB opened");
}
@Override
public void onConfigure(SQLiteDatabase db) {
super.onConfigure(db);
db.setForeignKeyConstraintsEnabled(true);
}
@Override
public synchronized void close() {
if(mDataBase != null)
mDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.d("DB","DB created");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion)
mNeedUpdate = true;
}
public ArrayList<Students> getAllData(){
ArrayList<Students> students = new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
try {
Cursor res = db.rawQuery("select * from "+TABLE_NAME1, null);
res.moveToFirst();
while(res.moveToNext()) {
int uid = Integer.parseInt(res.getString(0)); //0 is the number of id column in your database table
String name = res.getString(1);
String pass = res.getString(2);
String city = res.getString(3);
String centre = res.getString(4);
String inst = res.getString(5);
String pro = res.getString(6);
String batch = res.getString(7);
String days = res.getString(8);
String time = res.getString(9);
Students newStudents = new Students(uid,name,pass,city,centre,inst,pro,batch,days,time);
students.add(newStudents);
}
res.close();
}
catch(SQLiteException sql){
Log.d("DatabaseError!","No table found!");
}
finally {
db.close();
}
return students;
}
}
错误消息： E / SQLiteLog：（1）没有这样的表：StudentDetails D / DatabaseError !：找不到表！
答案 0 :(得分：0)
如果您拥有No such table error，则可以执行以下操作：
A。尝试增加数据库架构。
B。从设备上卸载应用程序，然后重新安装。
C。重命名表格，SQLite
答案 1 :(得分：0)
问题很可能是该设备是Android Pie或更高版本，在这种情况下，默认日志记录已从日志更改为WAL。
与
结合使用//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
将生成一个正在创建的数据库（以便创建数据库目录），然后该文件包括两个WAL dbname文件，后缀为-shm和-wal。
复制数据库时-wal和-shm文件与新数据库不匹配（它们属于覆盖的数据库）。
请参见此以获取修复程序A pre-populated database does not work at API 28 throws “no such table” exception
答案 2 :(得分：0)
显然，Android P设置了PRAGMA日志对象不同。仍然不知道是否会有副作用，但似乎正在起作用！
@Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
db.disableWriteAheadLogging();
}