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分割線
嵌套練習(xí)
2
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5
斜體
123
加粗
刪除線
小標(biāo)題
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- 2
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數(shù)字編碼
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表格
Tables | Are | Cool |
---|---|---|
col 3 is | right-aligned | $1600 |
col 2 is | centered | $12 |
zebra stripes | are neat | $1 |
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代碼測試
public class DataBaseAdapter {
MyDatabasesHelper db;
public DataBaseAdapter(Context context) {
db = new MyDatabasesHelper(context);
}
//增加數(shù)據(jù)操作
public void add(Emp e) {
SQLiteDatabase sq = db.getWritableDatabase(); //獲取數(shù)據(jù)庫寫權(quán)限
ContentValues values = new ContentValues();
values.put(MyDatabasesHelper.NAME, e.getName());
values.put(MyDatabasesHelper.AGE, e.getAge());
values.put(MyDatabasesHelper.SEX, e.getSex());
values.put(MyDatabasesHelper.SALARY, e.getSalary());
sq.insertOrThrow(MyDatabasesHelper.TAB_NAME, null, values);
// sq.execSQL("INSERT INTO emp(name,age,sex)VALUES(\'"+e.getName()+"\',"+e.getAge()+",\'"+e.getSex()+"\'"+")");
Log.i("add", e.toString());
}
//修改數(shù)據(jù)操作
public void update(Emp e) {
SQLiteDatabase sq = db.getWritableDatabase(); //獲取數(shù)據(jù)庫寫權(quán)限
ContentValues values = new ContentValues();
values.put(MyDatabasesHelper.NAME, e.getName());
values.put(MyDatabasesHelper.AGE, e.getAge());
values.put(MyDatabasesHelper.SEX, e.getSex());
values.put(MyDatabasesHelper.SALARY, e.getSalary());
sq.update(db.TAB_NAME, values, MyDatabasesHelper.ID + "=?", new String[]{String.valueOf(e.getId())});
db.close();
}
//刪除數(shù)據(jù)操作
public void delete(int id) {
SQLiteDatabase sq = db.getWritableDatabase(); //獲取數(shù)據(jù)庫寫權(quán)限
sq.delete(MyDatabasesHelper.TAB_NAME, "id=?", new String[]{String.valueOf(id)});
}
//查詢單個數(shù)據(jù)操作
public Emp find(int id) {
Emp emp = null;
SQLiteDatabase sq = db.getReadableDatabase(); //獲取數(shù)據(jù)庫寫權(quán)限
String table = MyDatabasesHelper.TAB_NAME;
String[] columns = new String[]{MyDatabasesHelper.ID,
MyDatabasesHelper.NAME,
MyDatabasesHelper.SEX,
MyDatabasesHelper.AGE,
MyDatabasesHelper.SALARY};
Cursor result = sq.query(table
, columns
, "id=?", new String[]{String.valueOf(id)}
, null, null, null);
while (result.moveToNext()) {
emp = new Emp();
emp.setId(result.getInt(0));
emp.setName(result.getString(1));
emp.setAge(result.getInt(2));
emp.setSalary(result.getDouble(3));
}
return emp;
}
//查詢所有數(shù)據(jù)操作
public List<Emp> findAll() {
List<Emp> list = new ArrayList<>();
SQLiteDatabase sq = db.getReadableDatabase(); //獲取數(shù)據(jù)庫寫權(quán)限
String table = MyDatabasesHelper.TAB_NAME;
String[] columns = new String[]{MyDatabasesHelper.ID, MyDatabasesHelper.NAME, MyDatabasesHelper.AGE, MyDatabasesHelper.SEX, MyDatabasesHelper.SALARY};
Cursor result = sq.query(table, columns, null, null, null, null, null);
while (result.moveToNext()) {
Emp emp = new Emp();
emp.setId(result.getInt(0));
emp.setName(result.getString(1));
emp.setAge(result.getInt(2));
emp.setSex(result.getString(3));
emp.setSalary(result.getDouble(4));
Log.i("tag", emp.toString());
list.add(emp);
}
return list;
}
//刪除數(shù)據(jù)庫
public void dropTable() {
SQLiteDatabase sq = db.getWritableDatabase();
sq.execSQL("drop table emp");
}
//創(chuàng)建數(shù)據(jù)表
public void createTable() {
SQLiteDatabase sq = db.getWritableDatabase();
sq.execSQL(MyDatabasesHelper.CREATE_TABLE);
}
}