android SQLite没有这样的表（代码1）错误

Question

我在我的android项目中导入一个SQLite数据库（进入assets文件夹）。我想访问它并显示记录。但是当我尝试它。得到那个错误

DatabaseHelper Class

public class DatabaseHelper extends SQLiteOpenHelper {
static String DB_PATH;
//Veritabanı ismini veriyoruz
static String DB_NAME = "ogrenci";

SQLiteDatabase myDatabase;

final Context myContext;

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

    DB_PATH = context.getFilesDir().getParent() + "/databases/";

    this.myContext = context;
}
//Assest dizinine koyduğumuz sql dosyasını, Android projesi içine oluşturma ve kopyalamna işlemi yapıldı..
public void CreateDataBase()
{
    boolean dbExists = checkDataBase();

    if (!dbExists)
    {
        this.getReadableDatabase();

        try
        {
            copyDataBase();
        }
        catch (Exception ex)
        {
            Log.w("hata","Veritabanı kopyalanamıyor");
            throw new Error("Veritabanı kopyalanamıyor.");
        }
    }
}
//Sqlite veritabanı dosyasını açıp, veritabanımı kontrol ediyoruz
boolean checkDataBase()
{
    SQLiteDatabase checkDB = null;

    try
    {
        String myPath = DB_PATH + DB_NAME;

        checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
    }
    catch (Exception ex)
    {
        Log.w("hata","Veritabanı açılamadı");
    }

    if (checkDB != null)
        checkDB.close();

    return checkDB != null ? true : false;
}
///Assest dizinine koyduğumuz sql dosyasındaki verileri kopyalıyoruz
void copyDataBase()
{
    try
    {
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        String outFileName = DB_PATH + DB_NAME;

        OutputStream myOutput = new FileOutputStream(outFileName);

        byte[] buffer = new byte[1024];

        int length;

        while ((length = myInput.read(buffer)) > 0)
        {
            myOutput.write(buffer, 0, length);
        }

        myOutput.flush();

        myInput.close();
        myOutput.close();
    }
    catch (Exception ex)
    {
        Log.w("hata", "Kopya oluşturma hatası.");
    }
}
//Veritabannı açma işlemi yapıldı

void openDataBase()
{
    String myPath = DB_PATH + DB_NAME;

    myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}

@Override
public synchronized void close()
{
    if (myDatabase != null && myDatabase.isOpen())
        myDatabase.close();

    super.close();
}

@Override
public void onCreate(SQLiteDatabase db) {

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

}

Corba1班

public class F_corba1 extends Fragment {

View parent;
Context con;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

   // text_baslik=(TextView)parent.findViewById(R.id.text_baslik);

    parent=inflater.inflate(R.layout.corba1,container,false);
    con=inflater.getContext();

    //DatabaseHelper sınıfımızdaki CreateDataBase methodunu çağırıp , assest dizinine koymuş
    //olduğumuz veritabanını,Android projesinin içinde  oluşturup,verileri kopyalamasını sağladık...
    DatabaseHelper dbHelper=new DatabaseHelper(con);
    try
    {
        dbHelper.CreateDataBase();

    }
    catch (Exception ex)
    {
        Log.w("hata","Veritabanı oluşturulamadı ve kopyalanamadı!");
    }


    //Proje içine kopyalanmış olan veritabanımızdan verileri listview e yazdırdık

    SQLiteDatabase db=dbHelper.getReadableDatabase();
    String[] getColumnName={"student_name,student_surname"};
    Cursor imlec=db.query("student", getColumnName, null, null, null, null, null);
    ListView listview=(ListView)parent.findViewById(R.id.listview);
    ArrayList<String> student=new ArrayList<String>();
    ArrayAdapter<String> adapter=new ArrayAdapter<String>(con,android.R.layout.simple_spinner_dropdown_item,student);

    while(imlec.moveToNext()){
        String student_name=imlec.getString(imlec.getColumnIndex("student_name"));
        String student_surname=imlec.getString(imlec.getColumnIndex("student_surname"));
        String name_surname= student_name+ " "+student_surname;
        student.add(name_surname);

    }
    listview.setAdapter(adapter);
    imlec.close();
    db.close();

    return parent;
}


}

错误日志

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.yeni, PID: 26479
    android.database.sqlite.SQLiteException: no such table: student (code 1): , while compiling: SELECT student_name,student_surname FROM student
        at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
        at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
        at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
        at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
        at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
        at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
        at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
        at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
        at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1161)
        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1032)
        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1200)
        at com.yeni.corbalar.F_corba1.onCreateView(F_corba1.java:63)
        at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299)
        at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595)
        at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
        at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149)
        at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
        at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5001)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

错误行（F_corba1.java:63）

 Cursor imlec=db.query("student", getColumnName, null, null, null, null, null);

Answer 1

我认为你的数据库路径是错误的。在您的情况下，您可以在资产文件夹中获取数据库的路径，如下所示：

DB_PATH = "file:///android_asset/School.db"

或者您可以将数据库作为InputStream获取：

InputStream dbInputStream = context.getAssets().open("School.db");

Answer 2

试试这个：

DatabaseHelper Class

public class DatabaseHelper extends SQLiteOpenHelper {
static String DB_PATH;
//Veritabanı ismini veriyoruz
static String DB_NAME = "School.db";

Answer 3

用下面的代码替换你的代码。

 public class F_corba1 extends Fragment {

View parent;
Context con;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                     Bundle savedInstanceState) {
 // text_baslik=(TextView)parent.findViewById(R.id.text_baslik);

parent=inflater.inflate(R.layout.corba1,container,false);
con=inflater.getContext();

//DatabaseHelper sınıfımızdaki CreateDataBase methodunu çağırıp , assest dizinine koymuş
//olduğumuz veritabanını,Android projesinin içinde  oluşturup,verileri kopyalamasını sağladık...
DatabaseHelper dbHelper=new DatabaseHelper(con);
try
{
    dbHelper.CreateDataBase();
    dbHelper.copyDataBase();

}
catch (Exception ex)
{
    Log.w("hata","Veritabanı oluşturulamadı ve kopyalanamadı!");
}


//Proje içine kopyalanmış olan veritabanımızdan verileri listview e yazdırdık

SQLiteDatabase db=dbHelper.getReadableDatabase();
String[] getColumnName={"student_name,student_surname"};
Cursor imlec=db.query("student", getColumnName, null, null, null, null, null);
ListView listview=(ListView)parent.findViewById(R.id.listview);
ArrayList<String> student=new ArrayList<String>();
ArrayAdapter<String> adapter=new ArrayAdapter<String>(con,android.R.layout.simple_spinner_dropdown_item,student);

while(imlec.moveToNext()){
    String student_name=imlec.getString(imlec.getColumnIndex("student_name"));
    String student_surname=imlec.getString(imlec.getColumnIndex("student_surname"));
    String name_surname= student_name+ " "+student_surname;
    student.add(name_surname);

}
listview.setAdapter(adapter);
imlec.close();
db.close();

return parent;
}
}

Answer 4

你不能在资产文件夹中使用db。 assets文件夹只是为了读取您无法保存或更新此文件夹中的任何文件。

Answer 5

您没有copied数据库School.db到ogrenci。只需使用copyDataBase() DatabaseHelper方法调用onCreate()方法。

试试这个：

@Override
public void onCreate(SQLiteDatabase db) {
    copyDataBase();
}

希望这会有所帮助〜