插入数据以在sqlite中记录 [英] Inserting data to record in sqlite

问题描述

我必须制作一个Android应用程序，其中必须使用sqlite存储数据来存储预定义的问题和答案。我找到了一些教程，每次我们运行该应用程序时都会在其中插入值，但是我必须在程序中插入这些问题和答案才能创建数据库。
有人可以向我建议任何教程，解释如何在表中插入值吗？

I have to make an Android application in which i have to store predefined question and answer, using sqlite to store data. I found tutorials in which values are inserted every time we run the application, but i have to insert these questions and answers in the program to make my database. Can someone suggest me any tutorial wich explain how to insert the values in table?

推荐答案

首先下载sqlite浏览器并打开您的.db文件（理想情况下应位于您的资产文件夹中），然后插入所有

First of all download sqlite browser and open your .db file which ideally should be in your assets folder, and insert all the records in respective table either manually or by query.

然后保存该db文件并将该文件复制到项目的资产文件夹中。

Then save that db file and copy that file in the assets folder of your project.

然后创建databasehelper类，并使其扩展SQLiteOpenHelper并定义数据库和所有函数以在那获取数据。

Then create databasehelper class and make it extend SQLiteOpenHelper and define your database and all the functions to fetch data over there.

让我知道您是否还有其他疑问：）

Let me know if you have further doubts :)

下载sqlite浏览器

DatabaseHelper.java

DatabaseHelper.java

public class DataBaseHelper extends SQLiteOpenHelper {

// The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.tutionimage/databases/";
private static String DB_NAME = "master_subject.db";
private SQLiteDatabase myDatabase;
private final Context myContext;
private boolean add2;

/**
 * Constructor Takes and keeps a reference of the passed context in order to
 * access to the application assets and resources.
 * 
 * @param context
 */
public DataBaseHelper(Context context) {
    super(context, DB_NAME, null, 1);
    this.myContext = context;
}

/**
 * Creates a empty database on the system and rewrites it with your own
 * database.
 * */
public void createDataBase() throws IOException {
    boolean dbExist = checkDataBase();
    if (dbExist) {
        // 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");
        }
    }
}

/**
 * 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_READONLY);
    } catch (SQLiteException e) {
        // database does't exist yet.
    }
    if (checkDB != null) {
        checkDB.close();
    }
    return checkDB != null ? true : false;
}

/**
 * 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 transfering bytestream.
 * */
private void copyDataBase() throws IOException {
    // Open your local db as the input stream
    InputStream myInput = myContext.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 inputfile to the outputfile
    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();

    // Toast.makeText(myContext, "Copy Done", 300).show();
}

public void openDataBase() throws SQLException {
    // Open the database
    String myPath = DB_PATH + DB_NAME;
    myDatabase = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READWRITE);

}

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

@Override
public void onCreate(SQLiteDatabase db) {

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Add your public helper methods to access and get content from the
    // database.
    // You could return cursors by doing "return myDatabase.query(....)" so
    // it'd be easy
    // to you to create adapters for your views.
}

//Insert Title into database
public long insertTitle(String sem, String subject,String jee, String chp, String marks, String time) {

    ContentValues initialValues = new ContentValues();

    initialValues.put("sem", sem);
    initialValues.put("subject", subject);
    initialValues.put("jee_flag", jee);
    initialValues.put("chapter", chp);
    initialValues.put("marks", marks);
    initialValues.put("time", time);

    return myDatabase.insert("testdata", null, initialValues);
}

//Fetching data from the database
public Cursor getTestData() throws SQLException{

    Cursor cursor = null;
    String queryString = "";


        if(NewStartPanel.queryString.split("-")[2].equalsIgnoreCase("n")){

            queryString = "select * from testdata where jee_flag='n' order by id desc";

        }

        else if(NewStartPanel.queryString.split("-")[2].equalsIgnoreCase("y")){

            queryString = "select * from testdata where jee_flag='y' order by id desc";
        }

        System.out.println("Query String:................  "+queryString);
        cursor = myDatabase.rawQuery(queryString, null);

    //  cursor.moveToFirst();

        System.out.println("cursor count of testdata is:"+cursor.getCount());


    return cursor;

}

TestOrReport.java

TestOrReport.java

    public class TestOrReport extends Activity implements OnClickListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.test_or_report);

    // set resources

    //Interacting with database

    DataBaseHelper dataBaseHelper =new DataBaseHelper(this);
    System.out.println("Before open db");
    dataBaseHelper.openDataBase();

    System.out.println("After open db");
    Cursor mCursor = dataBaseHelper.getTestData();

    System.out.println("@@ total rows :"+mCursor.getCount());


    // Then you can iterate through cursor and get those data in arraylist or whatever collection you want to
    }

    }

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