我有一个Android Quote应用程序，其中我使用SQLite数据库存储引号。我已经使用此DatabaseHelper启动了该应用程序的第一个版本。
public class DataBaseHandler extends SQLiteOpenHelper {
private static String DB_PATH;
private static String DB_NAME = "SuccessQuotes";
private SQLiteDatabase myDataBase;
private static int DATABASE_VERSION = 1;
private final Context myContext;
public DataBaseHandler(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
DB_PATH = context.getDatabasePath(DB_NAME).toString();
Log.e("path", DB_PATH);
}
// ==============================================================================
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
// do nothing - database already exist
} else {
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
// ==============================================================================
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH;
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;
}
// ==============================================================================
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;
// 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();
}
// ==============================================================================
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
// ==============================================================================
@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) {
}
}
我的数据库活动是：
public class DAO {
// All Static variables
private SQLiteDatabase database;
private DataBaseHandler dbHandler;
private static final String TABLE_QUOTES = "quotes";
private static final String TABLE_AUTHORS = "authors";
private static final String TABLE_SETTINGS = "settings";
// Pages Table Columns names
private static final String QU_ID = "_quid";
private static final String QU_TEXT = "qu_text";
private static final String QU_AUTHOR = "qu_author";
private static final String QU_FAVORITE = "qu_favorite";
private static final String QU_WEB_ID = "qu_web_id";
private static final String AU_ID = "_auid";
private static final String AU_NAME = "au_name";
private static final String AU_PICTURE = "au_picture";
private static final String AU_PICTURE_SDCARD = "au_picture_sdcard";
private static final String AU_WEB_ID = "au_web_id";
// ==============================================================================
public DAO(Context context) {
dbHandler = new DataBaseHandler(context);
try {
dbHandler.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
dbHandler.openDataBase();
} catch (SQLException sqle) {
throw sqle;
}
// Log.e("path2", context.getDatabasePath("SuccessQuotes").toString());
// open();
}
// ==============================================================================
// Getting All Quotes
public Cursor getQuotes(String start) {
// Select All Query
String limit = "15";
if (start.equals("5000")) {
String query_count = "SELECT COUNT(" + QU_ID + ") AS count FROM "
+ TABLE_QUOTES;
Cursor c_count = database.rawQuery(query_count, null);
c_count.moveToFirst();
Integer count = c_count.getInt(c_count.getColumnIndex("count"));
limit = String.valueOf(count);
}
String query = "SELECT * FROM " + TABLE_QUOTES + " JOIN "
+ TABLE_AUTHORS + " ON " + QU_AUTHOR + " = " + AU_WEB_ID
+ " ORDER BY " + QU_WEB_ID + " DESC "+ " LIMIT " + start + ", " + limit;
//Log.i("query",query);
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
// ==============================================================================
// Getting All Quotes
public Cursor getFavoriteQuotes(String start) {
// Select All Query
String limit = "15";
String query = "SELECT * FROM " + TABLE_QUOTES + " JOIN "
+ TABLE_AUTHORS + " ON " + QU_AUTHOR + " = " + AU_WEB_ID
+ " WHERE " + QU_FAVORITE + " = " + "1"+" ORDER BY " + QU_WEB_ID + " DESC "+ " LIMIT " + start + ", " + limit;
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
//======================================================================
// Getting Fav Quote from ID
public String getFavQuotes(String strkey_id) {
// Select All Query
String fav = "";
String query = "SELECT * FROM " + TABLE_QUOTES + " JOIN "
+ TABLE_AUTHORS + " ON " + QU_AUTHOR + " = " + AU_WEB_ID
+ " WHERE " + QU_FAVORITE + " = " + "1 AND " + QU_ID + " = " +strkey_id;
Cursor cursor = database.rawQuery(query, null);
if(cursor.getCount() != 0)
{
cursor.moveToFirst();
fav = cursor.getString(cursor.getColumnIndex(QU_FAVORITE));
}
return fav;
}
// ==============================================================================
// Getting All Author Quotes
public Cursor getAuthorQuotes(String authorID,String start) {
// Select All Query
String limit="15";
String query = "SELECT * FROM " + TABLE_QUOTES + " JOIN "
+ TABLE_AUTHORS + " ON " + QU_AUTHOR + " = " + AU_WEB_ID
+ " WHERE " + QU_AUTHOR + " = " + authorID + " ORDER BY "+ QU_WEB_ID +" DESC "+ " LIMIT " + start + ", " + limit;
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
// ==============================================================================
// Getting Selected Quote
public Cursor getOneQuote(String quoteID) {
// Select All Query
String query = "SELECT * FROM " + TABLE_QUOTES + " JOIN "
+ TABLE_AUTHORS + " ON " + QU_AUTHOR + " = " + AU_WEB_ID
+ " WHERE " + QU_ID + " = '" + quoteID + "'";
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
// ==============================================================================
public void addOrRemoveFavorites(String id, String value) {
ContentValues values = new ContentValues();
values.put(QU_FAVORITE, value);
// Update Row
// database.update(TABLE_QUOTES, values, QU_ID + "=?", new String[] { id });
database.update(TABLE_QUOTES, values, QU_ID + "=?", new String[] { id });
}
// ==============================================================================
// Getting All Authors
public Cursor getAllAuthors() {
// Select All Query
String query = "SELECT *, COUNT(" + QU_AUTHOR + ") AS count FROM "
+ TABLE_AUTHORS + " LEFT JOIN " + TABLE_QUOTES + " ON " + AU_WEB_ID
+ " = " + QU_AUTHOR + " GROUP BY " + AU_NAME ;
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
// ==============================================================================
// Getting Quotes Count
public Integer getQuotesCount() {
String query = "SELECT COUNT(" + QU_TEXT + ") AS count FROM "
+ TABLE_QUOTES;
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
Integer count = cursor.getInt(cursor.getColumnIndex("count"));
return count;
}
// ==============================================================================
// Getting Quote ID
public Integer getQotdId() {
String query = "SELECT " + QU_ID + " FROM " + TABLE_QUOTES
+ " ORDER BY RANDOM() LIMIT 1";
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
Integer id = cursor.getInt(cursor.getColumnIndex(QU_ID));
return id;
}
// ==============================================================================
public void updateSetting(String field, String value) {
open();
ContentValues values = new ContentValues();
values.put(field, value);
// Update Row
database.update(TABLE_SETTINGS, values, null, null);
}
// ==============================================================================
public Cursor getSettings() {
open();
String query = "SELECT * FROM " + TABLE_SETTINGS;
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor;
}
// ==============================================================================
public int getLastAuthor() {
String query = "SELECT " + AU_WEB_ID + " FROM " + TABLE_AUTHORS
+ " ORDER BY " + AU_WEB_ID + " DESC LIMIT 1";
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor.getInt(cursor.getColumnIndex(AU_WEB_ID));
}
// ==============================================================================
public int getLastQuote() {
String query = "SELECT " + QU_WEB_ID + " FROM " + TABLE_QUOTES
+ " ORDER BY " + QU_WEB_ID + " DESC LIMIT 1";
Cursor cursor = database.rawQuery(query, null);
cursor.moveToFirst();
return cursor.getInt(cursor.getColumnIndex(QU_WEB_ID));
}
// ==============================================================================
public void addAuthor(String au_name, String au_picture, int au_web_id) {
open();
ContentValues v = new ContentValues();
v.put(AU_NAME, au_name);
v.put(AU_PICTURE, au_picture);
v.put(AU_PICTURE_SDCARD, 1);
v.put(AU_WEB_ID, au_web_id);
database.insert(TABLE_AUTHORS, null, v);
}
// ==============================================================================
public void addQuote(String qu_text, int qu_author, int qu_web_id) {
open();
ContentValues v = new ContentValues();
v.put(QU_TEXT, qu_text);
v.put(QU_AUTHOR, qu_author);
v.put(QU_FAVORITE, "0");
v.put(QU_WEB_ID, qu_web_id);
database.insert(TABLE_QUOTES, null, v);
}
// ==============================================================================
public void open() throws SQLException {
// database = dbHandler.getReadableDatabase();
database = dbHandler.getWritableDatabase();
}
// ==============================================================================
public void closeDatabase() {
dbHandler.close();
}
现在，如果我想更新带有更多引号的应用程序，我应该做哪些更改，以便新旧用户不会遇到任何问题？
我不是Android开发人员的专家，所以请尽可能多解释一下，我会非常感谢。 感谢
由于
答案 0 :(得分：0)
试试这个只是添加引用到数据库就像这样我在这里添加联系方式相同的方式你可以添加引用到数据库
//Add new Contact by calling this method public void addContact(Contact contact) { // getting db instance for writing the contact SQLiteDatabase db=this.getWritableDatabase(); ContentValues cv=new ContentValues(); cv.put(Contact_fname,contact.getFname()); cv.put(Contact_lname,contact.getLname()); cv.put(Contact_number,contact.getContactnumber()); //inserting row db.insert(Table_Name, null, cv); //close the database to avoid any leak db.close(); }请参阅此处https://androidruler.wordpress.com/2016/02/22/android-working-with-sqlite-database/
答案 1 :(得分：0)
只需增加database version，onUpgrade()就会自动调用
private static int DATABASE_VERSION = 2;
并在此函数中添加数据库表字段
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}