Android SQLite使用

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讲解一下SQLite的用法：（不讲sql的语句）

/******真删改查的方法全写这里面*******/

public class DBHelper extends SQLiteOpenHelper {

private SQLiteDatabase db ;

public DBHelper(Context context) {

//上下文，数据库名字,数据库工厂，数据库版本

//第一个参数是数据库名字，第二个Null即可，第三个是数据库版本号，用来做判断升级的

super(context, Constants.DETAIL_ID_DBNAME, null,

Constants. DETAIL_ID_VERSION);

//得到一个可写的数据库

db = super.getWritableDatabase();

}

@Override

public void onCreate(SQLiteDatabase db) {

//在创建的时候直接创建一张表

String sql = "CREATE TABLE IF NOT EXISTS DETAIL ( deal_id TEXT PRIMARY KEY NOT NULL, image TEXT,brand_name TEXT,short_title TEXT,sell_count TEXT,groupon_price TEXT, market_price)";

db.execSQL(sql);

}

//这个是如果升级了数据库的版本，则会调用这个方法，数据库升级的时候，如果增加或者减少了字段，可以在这里面进行sql语句操作

@Override

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

if (newVersion > oldVersion) {//判断新版本的数据库的版本是否大于旧版本

onCreate(db);

}

public void excuteSQL(String sql, Object... bindArgs) {

db.execSQL(sql, bindArgs);

}

// 插入

public long insert(String table, String nullColumnHack, ContentValues values) {

long rows = 0;

rows = db.insert(table, nullColumnHack, values);

return rows;

}

// 查询

public Cursor query(String table, String[] columns, String selection,

String[] selectionArgs, String groupBy, String having,

String orderBy) {

return db .query(table, columns, selection, selectionArgs, groupBy,

having, orderBy);

}

public Cursor query(String sql, String... selectionArgs) {

return db .rawQuery(sql, selectionArgs);

}

public void destory() {

if (db != null) {

db.close();

}

/*******************调用*****************************************/

//查询

private List<Tuan> queryData() {

db = new DBHelper(CollectionDetailActivity.this);

List<Tuan> list = new ArrayList<Tuan>();

Cursor cursor = db.query( "select * from "

+ Constants. DETAIL_ID_TABLENAME);

while (cursor.moveToNext()) {

Tuan tuan = new Tuan();

tuan.setDeal_id(cursor.getString((cursor.getColumnIndex( "deal_id"))));

tuan.setImage(cursor.getString((cursor.getColumnIndex( "image"))));

tuan.setBrand_name(cursor.getString((cursor

.getColumnIndex( "brand_name"))));

tuan.setShort_title(cursor.getString((cursor

.getColumnIndex( "short_title"))));

tuan.setSale_count(cursor.getString((cursor

.getColumnIndex( "sell_count"))));

tuan.setGroupon_price(cursor.getString((cursor

.getColumnIndex( "groupon_price"))));

tuan.setMarket_price(cursor.getString((cursor

.getColumnIndex( "market_price"))));

tuan.setImageBitmap(ImageUtil. getImage(tuan.getImage()));

list.add(tuan);

}

return list;

}

//插入

db = new DBHelper(ProductDetails.this);

db.excuteSQL(Constants. DETAIL_INSERT, tuan.getDeal_id(),

tuan.getImage(), tuan.getBrand_name(),

tuan.getShort_title(), tuan.getSale_count(),

tuan.getGroupon_price(), tuan.getMarket_price());

Toast. makeText(ProductDetails.this, "收藏成功" , Toast.LENGTH_SHORT )

.show();

Constants. DETAIL_INSERT="insert into DETAIL(deal_id,image,brand_name,short_title,sell_count,groupon_price,market_price) VALUES (?,?,?,?,?,?,?)";

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