Question

我的计算机上有一个数据库（localhost），有数千条记录。我只想将包含这些记录的表转换为可在Android上访问的数据库。我听说过SQLite，但是有没有将.sql文件转换为SQLite数据库并将其在我的Android手机上脱机存储？

Answer 1

是的，你可以这样做。首先，您需要将.sql文件转换为Android可以理解的sqlite数据库。在新的sqlite架构中，您需要

android_metadata表，并插入一个区域设置行。我将我的设置为“en_US”

CREATE TABLE android_metadata（locale TEXT）
用于保存数据的表格。您可以根据自己的喜好命名此表，但请确保将_id作为主键。例如

CREATE TABLE mydata（_id INTEGER PRIMARY KEY，data TEXT）

然后，您需要将.sql文件中的数据导入新数据表。您可能会发现SQLiteBrowser有用http://sourceforge.net/projects/sqlitebrowser/

一旦你完成了，你现在有了一个可以加载的sqlite数据库，并从你的Android应用程序中读取。

将sqlite数据库复制到android项目资产文件夹。然后，您可以创建数据库帮助程序，该数据库帮助程序将打开并构建您的应用程序可以访问的脱机sqlite数据库。

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
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 MyDbHelper extends SQLiteOpenHelper {
    // The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/yourpackagename/databases/";

    private static String DB_NAME = "your_db_name.db";

    private static final String DATA_TABLE_NAME = "your_data_table_name";
    private static final String COLUMN_YOUR_DATA_COLUMN_NAME = "data";

    private SQLiteDatabase myDataBase;

    private final Context myContext;

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

    /**
     * Function: createDataBase() 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.i("info", "db exists. do nothing");
            // 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.
            Log.i("info", "creating new db");
            this.getReadableDatabase();
            this.close();

            try {
                copyDataBase();
            } catch (IOException e) {
                close();
                throw new Error("Error copying database");
            }
        }
    }

    /**
     * Function: checkDataBase() 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;
    }

    /**
     * Function: copyDataBase() 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();

    }

    /**
     * Function: openDataBase()
     * 
     */
    public void openDataBase() throws SQLException {
        // Open the database
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null,
                SQLiteDatabase.OPEN_READONLY);
    }

    /**
     * Function: close()
     * 
     * @Override close() method
     */
    @Override
    public synchronized void close() {

        if (myDataBase != null)
            myDataBase.close();
        super.close();

    }

    /**
     * Function: onCreate()
     * 
     * @Override onCreate() method
     */
    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    /**
     * Function: onUpgrade()
     * 
     * @Override onUpgrade() method
     */
    @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.

}

将.sql表转换为SQLITE数据库？

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