Android中数据库常见操作实例分析

/** * 查询某条记录是否存在

* * @param name

* @return */

public boolean find(String name) { SQLiteDatabase db = dbHelper.getReadableDatabase();

Cursor cursor = db.rawQuery( "select * from user_table where userName = ?",

new String[] { name }); boolean result = cursor.moveToNext();

db.close(); return result;

} public boolean findAndroid(String name) {

SQLiteDatabase db = dbHelper.getReadableDatabase(); Cursor cursor = db.query(Table.USER_INFO_TB_NAME, null, "userName = ?",

new String[] { name }, null, null, null); boolean result = cursor.moveToNext();// true代表查找到了

db.close(); return result;

} /**

* 修改一条记录 *

* @param id * @param name

*/ public void update(String id, String name) {

SQLiteDatabase db = dbHelper.getWritableDatabase(); // 缺点无返回值

db.execSQL("update user_table set userName = ? where userId = ?", new Object[] { name, id });

db.close(); }

public int updateAndroid(String id, String name) { SQLiteDatabase db = dbHelper.getWritableDatabase();

ContentValues values = new ContentValues(); values.put("userName", name);

// 返回值大于0代表修改更新成功 int result = db.update(Table.USER_INFO_TB_NAME, values, "userId = ?",

new String[] { id }); db.close();

return result; }

/** * 删除一条记录