Question

我尝试使用SQLite在Android中创建数据库。我有一个单独的类将值插入数据库，但我收到的错误表明数据库无法创建，我不知道为什么！任何帮助将不胜感激。

package com.example.siuni.mymedicare;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.sql.SQLException;

/**
 * Created by SiUni on 23/04/2015.
 */

public class MyDBHandler {

    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_FIRSTNAME = "_firstname";
    public static final String COLUMN_SURNAME = "_surname";
    public static final String COLUMN_TELEPHONENO = "_telephoneno";
    public static final String COLUMN_POSTCODE = "_postcode";
    private static final String TAG = "MyDBHelper";
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "mymedicare.db";
    private static final String TABLE_DATABASEHANDLER = "Databasehandler";
    private static final String DATABASE_CREATE =
            "create table contacts (_id integer primary key autoincrement, " +
                    "name text not null, surname not null, telephoneno notnull, postcode not null);";
    public final Context context;
    private DatabaseHandler DBHandler;
    public SQLiteDatabase db;

    public MyDBHandler(Context ctx) {
        this.context = ctx;
        DBHandler = new DatabaseHandler(context);
    }

    private static class DatabaseHandler extends SQLiteOpenHelper {
        DatabaseHandler(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);

        }

        @Override
        public void onCreate(SQLiteDatabase db) {

            try {
                db.execSQL(DATABASE_CREATE);
            } catch (android.database.SQLException e) {
                e.printStackTrace();
            }

        }

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

            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS contacts");
            onCreate(db);
        }

    }


    public MyDBHandler open() throws SQLException {
        db = DBHandler.getWritableDatabase();
        return this;
    }

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

    public long insertContact(String Firstname, String Surname, String Telephone,
                              String Postcode) {

        ContentValues insertValues = new ContentValues();
        insertValues.put(COLUMN_FIRSTNAME, Firstname);
        insertValues.put(COLUMN_SURNAME, Surname);
        insertValues.put(COLUMN_TELEPHONENO, Telephone);
        insertValues.put(COLUMN_POSTCODE, Postcode);
        return db.insert(TABLE_DATABASEHANDLER, null, insertValues);
    }

    public Cursor getAllContacts ()
    {
        return db.query(TABLE_DATABASEHANDLER, new String [] {COLUMN_ID, COLUMN_FIRSTNAME,
    COLUMN_SURNAME}, null, null, null, null, null);
    }

    public Cursor getContact (long rowId) throws android.database.SQLException
    {
        Cursor mCursor =
                db.query(true, TABLE_DATABASEHANDLER, new String[] {COLUMN_ID, COLUMN_FIRSTNAME,
                COLUMN_SURNAME}, COLUMN_ID + "=" + rowId, null, null,null,null,null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return  mCursor;
    }

}

错误日志：

05-12 16:50:07.348    2466-2466/com.example.siuni.mymedicare E/SQLiteDatabase﹕ Error inserting _surname= _postcode= _telephoneno= _firstname=
    android.database.sqlite.SQLiteException: no such table: Databasehandler (code 1): , while compiling: INSERT INTO Databasehandler(_surname,_postcode,_telephoneno,_firstname) VALUES (?,?,?,?)
            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.SQLiteStatement.<init>(SQLiteStatement.java:31)
            at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
            at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
            at com.example.siuni.mymedicare.MyDBHandler.insertContact(MyDBHandler.java:85)
            at com.example.siuni.mymedicare.register.onCreate(register.java:45)
            at android.app.Activity.performCreate(Activity.java:5937)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

提前感谢您的帮助

Answer 1

问题在于：

byte[] byteArray = File.ReadAllBytes("C:\\temp\\sa123.potx"); using (MemoryStream stream = new MemoryStream()) { stream.Write(byteArray, 0, (int)byteArray.Length); using (PresentationDocument presentationDoc = PresentationDocument.Open(stream, true)) { // Change from template type to presentation type presentationDoc.ChangeDocumentType(PresentationDocumentType.Presentation); } File.WriteAllBytes("C:\\temp\\sa123.pptx", stream.ToArray()); }

在您的代码中，您使用private static final String TABLE_DATABASEHANDLER = "**Databasehandler**";作为表名，但您没有名为TABLE_DATABASEHANDLER的表。

从数据库创建语句中可以看出，您只有一个表 - Databasehandler： contacts

Answer 2

您正在尝试将值插入Databasehandler表，并且在您的创建SQL中只有一个表，称为contacts。 create table contacts (_id integer pr....
只需更改String TABLE_DATABASEHANDLER = "Databasehandler";变量的值

即可

无法创建数据库

2 个答案: