34
我想在我的應用程序中創建一個包含三個表的SQLite數據庫，我將在表中添加數據並稍後使用它們。在android中創建SQLite數據庫
但我喜歡保留數據庫，就好像應用程序第一次安裝時一樣，它會檢查數據庫是否存在，如果存在則更新它，否則創建新數據庫。
更多我正在製作一個數據庫類以方便我的應用程序，所以我不會爲我的數據庫創建創建活動。
，如果有可能的建議，請與我分享
A
回答
42
更好的例子是[這裏]
try {
myDB = this.openOrCreateDatabase("DatabaseName", MODE_PRIVATE, null);
/* Create a Table in the Database. */
myDB.execSQL("CREATE TABLE IF NOT EXISTS "
+ TableName
+ " (Field1 VARCHAR, Field2 INT(3));");
/* Insert data to a Table*/
myDB.execSQL("INSERT INTO "
+ TableName
+ " (Field1, Field2)"
+ " VALUES ('Saranga', 22);");
/*retrieve data from database */
Cursor c = myDB.rawQuery("SELECT * FROM " + TableName , null);
int Column1 = c.getColumnIndex("Field1");
int Column2 = c.getColumnIndex("Field2");
// Check if our result was valid.
c.moveToFirst();
if (c != null) {
// Loop through all Results
do {
String Name = c.getString(Column1);
int Age = c.getInt(Column2);
Data =Data +Name+"/"+Age+"\n";
}while(c.moveToNext());
}
1
爲什麼不是指documentation或示例代碼與SDK出貨？示例中的代碼介紹瞭如何使用鏈接的文檔中描述的幫助程序類創建/更新/填充/讀取數據庫。
5
如果你想保持數據庫之間的卸載，你必須把它放在SD卡上。這是您的應用程序被刪除時唯一不會被刪除的地方。但是作爲回報，它可以被用戶每次刪除。
如果你把數據庫放在SD卡上，你不能再使用SQLiteOpenHelper，但是你可以使用這個類的源代碼和體系結構來獲得關於如何實現創建，更新和打開DATABSE。
2
這是完整的源代碼，直接使用，
public class CardDBDAO {
protected SQLiteDatabase database;
private DataBaseHelper dbHelper;
private Context mContext;
public CardDBDAO(Context context) {
this.mContext = context;
dbHelper = DataBaseHelper.getHelper(mContext);
open();
}
public void open() throws SQLException {
if(dbHelper == null)
dbHelper = DataBaseHelper.getHelper(mContext);
database = dbHelper.getWritableDatabase();
}
}
public class DataBaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "mydbnamedb";
private static final int DATABASE_VERSION = 1;
public static final String CARDS_TABLE = "tbl_cards";
public static final String POICATEGORIES_TABLE = "tbl_poicategories";
public static final String POILANGS_TABLE = "tbl_poilangs";
public static final String ID_COLUMN = "id";
public static final String POI_ID = "poi_id";
public static final String POICATEGORIES_COLUMN = "poi_categories";
public static final String POILANGS_COLUMN = "poi_langs";
public static final String CARDS = "cards";
public static final String CARD_ID = "card_id";
public static final String CARDS_PCAT_ID = "pcat_id";
public static final String CREATE_PLANG_TABLE = "CREATE TABLE "
+ POILANGS_TABLE + "(" + ID_COLUMN + " INTEGER PRIMARY KEY,"
+ POILANGS_COLUMN + " TEXT, " + POI_ID + " TEXT)";
public static final String CREATE_PCAT_TABLE = "CREATE TABLE "
+ POICATEGORIES_TABLE + "(" + ID_COLUMN + " INTEGER PRIMARY KEY,"
+ POICATEGORIES_COLUMN + " TEXT, " + POI_ID + " TEXT)";
public static final String CREATE_CARDS_TABLE = "CREATE TABLE "
+ CARDS_TABLE + "(" + ID_COLUMN + " INTEGER PRIMARY KEY," + CARD_ID
+ " TEXT, " + CARDS_PCAT_ID + " TEXT, " + CARDS + " TEXT)";
private static DataBaseHelper instance;
public static synchronized DataBaseHelper getHelper(Context context) {
if (instance == null)
instance = new DataBaseHelper(context);
return instance;
}
private DataBaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
if (!db.isReadOnly()) {
// Enable foreign key constraints
// db.execSQL("PRAGMA foreign_keys=ON;");
}
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_PCAT_TABLE);
db.execSQL(CREATE_PLANG_TABLE);
db.execSQL(CREATE_CARDS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
public class PoiLangDAO extends CardDBDAO {
private static final String WHERE_ID_EQUALS = DataBaseHelper.ID_COLUMN
+ " =?";
public PoiLangDAO(Context context) {
super(context);
}
public long save(PLang plang_data) {
ContentValues values = new ContentValues();
values.put(DataBaseHelper.POI_ID, plang_data.getPoi_id());
values.put(DataBaseHelper.POILANGS_COLUMN, plang_data.getLangarr());
return database
.insert(DataBaseHelper.POILANGS_TABLE, null, values);
}
public long update(PLang plang_data) {
ContentValues values = new ContentValues();
values.put(DataBaseHelper.POI_ID, plang_data.getPoi_id());
values.put(DataBaseHelper.POILANGS_COLUMN, plang_data.getLangarr());
long result = database.update(DataBaseHelper.POILANGS_TABLE,
values, WHERE_ID_EQUALS,
new String[] { String.valueOf(plang_data.getId()) });
Log.d("Update Result:", "=" + result);
return result;
}
public int deleteDept(PLang plang_data) {
return database.delete(DataBaseHelper.POILANGS_TABLE,
WHERE_ID_EQUALS, new String[] { plang_data.getId() + "" });
}
public List<PLang> getPLangs1() {
List<PLang> plang_list = new ArrayList<PLang>();
Cursor cursor = database.query(DataBaseHelper.POILANGS_TABLE,
new String[] { DataBaseHelper.ID_COLUMN, DataBaseHelper.POI_ID,
DataBaseHelper.POILANGS_COLUMN }, null, null, null,
null, null);
while (cursor.moveToNext()) {
PLang plang_bin = new PLang();
plang_bin.setId(cursor.getInt(0));
plang_bin.setPoi_id(cursor.getString(1));
plang_bin.setLangarr(cursor.getString(2));
plang_list.add(plang_bin);
}
return plang_list;
}
public List<PLang> getPLangs(String pid) {
List<PLang> plang_list = new ArrayList<PLang>();
String selection = DataBaseHelper.POI_ID + "=?";
String[] selectionArgs = { pid };
Cursor cursor = database.query(DataBaseHelper.POILANGS_TABLE,
new String[] { DataBaseHelper.ID_COLUMN, DataBaseHelper.POI_ID,
DataBaseHelper.POILANGS_COLUMN }, selection,
selectionArgs, null, null, null);
while (cursor.moveToNext()) {
PLang plang_bin = new PLang();
plang_bin.setId(cursor.getInt(0));
plang_bin.setPoi_id(cursor.getString(1));
plang_bin.setLangarr(cursor.getString(2));
plang_list.add(plang_bin);
}
return plang_list;
}
public void loadPLangs(String poi_id, String langarrs) {
PLang plangbin = new PLang(poi_id, langarrs);
List<PLang> plang_arr = new ArrayList<PLang>();
plang_arr.add(plangbin);
for (PLang dept : plang_arr) {
ContentValues values = new ContentValues();
values.put(DataBaseHelper.POI_ID, dept.getPoi_id());
values.put(DataBaseHelper.POILANGS_COLUMN, dept.getLangarr());
database.insert(DataBaseHelper.POILANGS_TABLE, null, values);
}
}
}
public class PLang {
public PLang() {
super();
}
public PLang(String poi_id, String langarrs) {
// TODO Auto-generated constructor stub
this.poi_id = poi_id;
this.langarr = langarrs;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getPoi_id() {
return poi_id;
}
public void setPoi_id(String poi_id) {
this.poi_id = poi_id;
}
public String getLangarr() {
return langarr;
}
public void setLangarr(String langarr) {
this.langarr = langarr;
}
private int id;
private String poi_id;
private String langarr;
}
2
public class MyDatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "MyDb.db";
private static final int DATABASE_VERSION = 1;
// Database creation sql statement
private static final String DATABASE_CREATE_FRIDGE_ITEM = "create table FridgeItem(id integer primary key autoincrement,f_id text not null,food_item text not null,quantity text not null,measurement text not null,expiration_date text not null,current_date text not null,flag text not null,location text not null);";
public MyDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Method is called during creation of the database
@Override
public void onCreate(SQLiteDatabase database) {
database.execSQL(DATABASE_CREATE_FRIDGE_ITEM);
}
// Method is called during an upgrade of the database,
@Override
public void onUpgrade(SQLiteDatabase database,int oldVersion,int newVersion){
Log.w(MyDatabaseHelper.class.getName(),"Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
database.execSQL("DROP TABLE IF EXISTS FridgeItem");
onCreate(database);
}
}
public class CommentsDataSource {
private MyDatabaseHelper dbHelper;
private SQLiteDatabase database;
public String stringArray[];
public final static String FOOD_TABLE = "FridgeItem"; // name of table
public final static String FOOD_ITEMS_DETAILS = "FoodDetails"; // name of table
public final static String P_ID = "id"; // pid
public final static String FOOD_ID = "f_id"; // id value for food item
public final static String FOOD_NAME = "food_item"; // name of food
public final static String FOOD_QUANTITY = "quantity"; // quantity of food item
public final static String FOOD_MEASUREMENT = "measurement"; // measurement of food item
public final static String FOOD_EXPIRATION = "expiration_date"; // expiration date of food item
public final static String FOOD_CURRENTDATE = "current_date"; // date of food item added
public final static String FLAG = "flag";
public final static String LOCATION = "location";
/**
*
* @param context
*/
public CommentsDataSource(Context context) {
dbHelper = new MyDatabaseHelper(context);
database = dbHelper.getWritableDatabase();
}
public long insertFoodItem(String id, String name,String quantity, String measurement, String currrentDate,String expiration,String flag,String location) {
ContentValues values = new ContentValues();
values.put(FOOD_ID, id);
values.put(FOOD_NAME, name);
values.put(FOOD_QUANTITY, quantity);
values.put(FOOD_MEASUREMENT, measurement);
values.put(FOOD_CURRENTDATE, currrentDate);
values.put(FOOD_EXPIRATION, expiration);
values.put(FLAG, flag);
values.put(LOCATION, location);
return database.insert(FOOD_TABLE, null, values);
}
public long insertFoodItemsDetails(String id, String name,String quantity, String measurement, String currrentDate,String expiration) {
ContentValues values = new ContentValues();
values.put(FOOD_ID, id);
values.put(FOOD_NAME, name);
values.put(FOOD_QUANTITY, quantity);
values.put(FOOD_MEASUREMENT, measurement);
values.put(FOOD_CURRENTDATE, currrentDate);
values.put(FOOD_EXPIRATION, expiration);
return database.insert(FOOD_ITEMS_DETAILS, null, values);
}
public Cursor selectRecords(String id) {
String[] cols = new String[] { FOOD_ID, FOOD_NAME, FOOD_QUANTITY, FOOD_MEASUREMENT, FOOD_EXPIRATION,FLAG,LOCATION,P_ID};
Cursor mCursor = database.query(true, FOOD_TABLE, cols, P_ID+"=?", new String[]{id}, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor; // iterate to get each value.
}
public Cursor selectAllName() {
String[] cols = new String[] { FOOD_NAME};
Cursor mCursor = database.query(true, FOOD_TABLE, cols, null, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor; // iterate to get each value.
}
public Cursor selectAllRecords(String loc) {
String[] cols = new String[] { FOOD_ID, FOOD_NAME, FOOD_QUANTITY, FOOD_MEASUREMENT, FOOD_EXPIRATION,FLAG,LOCATION,P_ID};
Cursor mCursor = database.query(true, FOOD_TABLE, cols, LOCATION+"=?", new String[]{loc}, null, null, null, null);
int size=mCursor.getCount();
stringArray = new String[size];
int i=0;
if (mCursor != null) {
mCursor.moveToFirst();
FoodInfo.arrayList.clear();
while (!mCursor.isAfterLast()) {
String name=mCursor.getString(1);
stringArray[i]=name;
String quant=mCursor.getString(2);
String measure=mCursor.getString(3);
String expir=mCursor.getString(4);
String id=mCursor.getString(7);
FoodInfo fooditem=new FoodInfo();
fooditem.setName(name);
fooditem.setQuantity(quant);
fooditem.setMesure(measure);
fooditem.setExpirationDate(expir);
fooditem.setid(id);
FoodInfo.arrayList.add(fooditem);
mCursor.moveToNext();
i++;
}
}
return mCursor; // iterate to get each value.
}
public Cursor selectExpDate() {
String[] cols = new String[] {FOOD_NAME, FOOD_QUANTITY, FOOD_MEASUREMENT, FOOD_EXPIRATION};
Cursor mCursor = database.query(true, FOOD_TABLE, cols, null, null, null, null, FOOD_EXPIRATION, null);
int size=mCursor.getCount();
stringArray = new String[size];
if (mCursor != null) {
mCursor.moveToFirst();
FoodInfo.arrayList.clear();
while (!mCursor.isAfterLast()) {
String name=mCursor.getString(0);
String quant=mCursor.getString(1);
String measure=mCursor.getString(2);
String expir=mCursor.getString(3);
FoodInfo fooditem=new FoodInfo();
fooditem.setName(name);
fooditem.setQuantity(quant);
fooditem.setMesure(measure);
fooditem.setExpirationDate(expir);
FoodInfo.arrayList.add(fooditem);
mCursor.moveToNext();
}
}
return mCursor; // iterate to get each value.
}
public int UpdateFoodItem(String id, String quantity, String expiration){
ContentValues values=new ContentValues();
values.put(FOOD_QUANTITY, quantity);
values.put(FOOD_EXPIRATION, expiration);
return database.update(FOOD_TABLE, values, P_ID+"=?", new String[]{id});
}
public void deleteComment(String id) {
System.out.println("Comment deleted with id: " + id);
database.delete(FOOD_TABLE, P_ID+"=?", new String[]{id});
}
}
1
要了解如何使用SQLite數據庫，Android的最佳實踐看 - Android with sqlite database
有幾個關於你應該知道的類，它們會幫助你模擬表和模型，即android.provider.BaseColumns
下面是一個表
public class ProductTable implements BaseColumns {
public static final String NAME = "name";
public static final String PRICE = "price";
public static final String TABLE_NAME = "products";
public static final String CREATE_QUERY = "create table " + TABLE_NAME + " (" +
_ID + " INTEGER, " +
NAME + " TEXT, " +
PRICE + " INTEGER)";
public static final String DROP_QUERY = "drop table " + TABLE_NAME;
public static final String SElECT_QUERY = "select * from " + TABLE_NAME;
}
0
這裏的例子是代碼
DatabaseMyHandler.class
public class DatabaseMyHandler extends SQLiteOpenHelper {
private SQLiteDatabase myDataBase;
private Context context = null;
private static String TABLE_NAME = "customer";
public static final String DATABASE_NAME = "Student.db";
public final static String DATABASE_PATH = "/data/data/com.pkgname/databases/";
public static final int DATABASE_VERSION = 2;
public DatabaseMyHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
try {
createDatabase();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
myDataBase = sqLiteDatabase;
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
}
//Check database already exists or not
private boolean checkDatabaseExists() {
boolean checkDB = false;
try {
String PATH = DATABASE_PATH + DATABASE_NAME;
File dbFile = new File(PATH);
checkDB = dbFile.exists();
} catch (SQLiteException e) {
}
return checkDB;
}
//Create a empty database on the system
public void createDatabase() throws IOException {
boolean dbExist = checkDatabaseExists();
if (dbExist) {
Log.v("DB Exists", "db exists");
}
boolean dbExist1 = checkDatabaseExists();
if (!dbExist1) {
this.getWritableDatabase();
try {
this.close();
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
//Copies your database from your local assets-folder to the just created empty database in the system folder
private void copyDataBase() throws IOException {
String outFileName = DATABASE_PATH + DATABASE_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
InputStream myInput = context.getAssets().open(DATABASE_NAME);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myInput.close();
myOutput.flush();
myOutput.close();
}
//Open Database
public void openDatabase() throws SQLException {
String PATH = DATABASE_PATH + DATABASE_NAME;
myDataBase = SQLiteDatabase.openDatabase(PATH, null, SQLiteDatabase.OPEN_READWRITE);
}
//for insert data into database
public void insertCustomer(String customer_id, String email_id, String password, String description, int balance_amount) {
try {
openDatabase();
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("customer_id", customer_id);
contentValues.put("email_id", email_id);
contentValues.put("password", password);
contentValues.put("description", description);
contentValues.put("balance_amount", balance_amount);
db.insert(TABLE_NAME, null, contentValues);
} catch (SQLException e) {
e.printStackTrace();
}
}
public ArrayList<ModelCreateCustomer> getLoginIdDetail(String email_id, String password) {
ArrayList<ModelCreateCustomer> result = new ArrayList<ModelCreateCustomer>();
//boolean flag = false;
String selectQuery = "SELECT * FROM " + TABLE_NAME + " WHERE email_id='" + email_id + "' AND password='" + password + "'";
try {
openDatabase();
Cursor cursor = myDataBase.rawQuery(selectQuery, null);
//cursor.moveToFirst();
if (cursor.getCount() > 0) {
if (cursor.moveToFirst()) {
do {
ModelCreateCustomer model = new ModelCreateCustomer();
model.setId(cursor.getInt(cursor.getColumnIndex("id")));
model.setCustomerId(cursor.getString(cursor.getColumnIndex("customer_id")));
model.setCustomerEmailId(cursor.getString(cursor.getColumnIndex("email_id")));
model.setCustomerPassword(cursor.getString(cursor.getColumnIndex("password")));
model.setCustomerDesription(cursor.getString(cursor.getColumnIndex("description")));
model.setCustomerBalanceAmount(cursor.getInt(cursor.getColumnIndex("balance_amount")));
result.add(model);
}
while (cursor.moveToNext());
}
Toast.makeText(context, "Login Successfully", Toast.LENGTH_SHORT).show();
}
// Log.e("Count", "" + cursor.getCount());
cursor.close();
myDataBase.close();
} catch (SQLException e) {
e.printStackTrace();
}
return result;
}
public void updateCustomer(String id, String email_id, String description, int balance_amount) {
try {
openDatabase();
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("email_id", email_id);
contentValues.put("description", description);
contentValues.put("balance_amount", balance_amount);
db.update(TABLE_NAME, contentValues, "id=" + id, null);
} catch (SQLException e) {
e.printStackTrace();
}
}
}
客戶.class
public class Customer extends AppCompatActivity{
private DatabaseMyHandler mydb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_customer);
mydb = new DatabaseMyHandler(CreateCustomerActivity.this);
mydb.insertCustomer("1", "[email protected]", "123", "test", 100);
}
}
0
一個簡單的數據庫示例，將今日生活的待辦事項列表插入到數據庫中，並獲取所有待辦事項列表的列表。
public class MyDatabaseHelper extends SQLiteOpenHelper {
// Logcat tag
private static final String LOG = "DatabaseHelper";
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "SQLiteDemoDB";
// Table Names
private static final String TABLE_TODO = "todos";
// column names
private static final String KEY_ID = "id";
private static final String KEY_CREATED_AT = "created_at";
private static final String KEY_TODO = "todoDescr";
// *********************************************************************************************
public MyDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE_TODO);
}
// Upgrading database **************************************************************************
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_TODO);
// Create tables again
onCreate(db);
}
// Creating Table TABLE_TEAM
String CREATE_TABLE_TODO = "CREATE TABLE " + TABLE_TODO + "("
+ KEY_ID + " integer primary key autoincrement, "
+ KEY_TODO + " text, "
+ KEY_CREATED_AT + " text" + ")";
// insert values of todo
public boolean InsertTodoDetails(String todo, String createdAt) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(KEY_TODO, todo);
contentValues.put(KEY_CREATED_AT, createdAt);
long rowInserted = db.insert(TABLE_TODO, null, contentValues);
db.close();
return true;
}
// Select values of todo
public Cursor GetAllTodoDetails() {
SQLiteDatabase db = this.getReadableDatabase();
String query = "SELECT * FROM " + TABLE_TODO;
Cursor mcursor = db.rawQuery(query, null);
if (mcursor != null) {
mcursor.moveToFirst();
}
return mcursor;
}
}
我的活動保存並獲取記錄。
public class MyDbActivity extends AppCompatActivity {
@Bind(R.id.edt_todo)
EditText edtTodo;
@Bind(R.id.btn_save)
Button btnSave;
MyDatabaseHelper db;
@Bind(R.id.btn_getTodo)
Button btnGetTodo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_db);
ButterKnife.bind(this);
// creating database object
db = new MyDatabaseHelper(this);
}
@OnClick(R.id.btn_save)
public void onViewClicked() {
String datetime = "";
try {
SimpleDateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
datetime = dateformat.format(new Date());
} catch (Exception e) {
e.printStackTrace();
}
db.InsertTodoDetails(edtTodo.getText().toString().trim(), datetime);
}
@OnClick(R.id.btn_getTodo)
public void onGetTodoClicked() {
String todos = "";
Cursor TodoList = db.GetAllTodoDetails();
if (TodoList.moveToFirst()) {
do {
if (todos.equals("")) {
todos = TodoList.getString(TodoList.getColumnIndex("todoDescr"));
} else {
todos = todos + ", " + TodoList.getString(TodoList.getColumnIndex("todoDescr"));
}
// do what ever you want here
} while (TodoList.moveToNext());
}
TodoList.close();
Toast.makeText(this, "" + todos, Toast.LENGTH_SHORT).show();
}
}
所以......這是個問題嗎？ – msysmilu 2015-01-29 09:12:53
這裏有完美而簡單的解釋，讓我們清楚地瞭解如何使用SQLite [點擊此處訪問資源]（http://www.codeproject.com/Articles/119293/Using-SQLite-Database-with -Android） – Devrath 2013-05-31 05:55:29