这是一篇最基本的sqlite使用,只为记录一下知识点,希望可以为初学者提供一些参考。
创建数据库,新建一个帮助类DBHelper继承SQLiteOpenHelper
public class DBHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "pay_order.db";
private static final int DATABASE_VERSION = 1;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE pay_order (code VARCHAR PRIMARY KEY, username VARCHAR, state VARCHAR)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS pay_order");
}
新建一个管理类DBmanager,处理对数据的增删改查,不啰嗦了,代码里有注释
package com.panku.sqlitedemo.db;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import java.util.ArrayList;
import java.util.List;
/**
* Date:2017/6/13
* Time: 12:00
* author: huangyanan
*/
public class DBManager {
private DBHelper dbHelper;
private SQLiteDatabase database;
public DBManager(Context context) {
dbHelper = new DBHelper(context);
database = dbHelper.getWritableDatabase();
}
/**
* 添加一组数据
*
* @param orders
*/
public void add(List orders) {
for (OrderInfo order : orders) {
ContentValues values = new ContentValues();
values.put("code", order.getCode());
values.put("username", order.getUsername());
values.put("state", order.getState());
database.insert("pay_order", null, values);
}
}
/**
* 添加一条数据
*
* @param order
*/
public void add(OrderInfo order) {
if (query(order.getCode()) == null) {
ContentValues values = new ContentValues();
values.put("code", order.getCode());
values.put("username", order.getUsername());
values.put("state", order.getState());
database.insert("pay_order", null, values);
} else {
Log.e("HYN", "订单已存在,已更新");
update(order);
}
}
/**
* 删除数据
*
* @param code
*/
public void delete(String code) {
int result = -1;//0失败1成功
result = database.delete("pay_order", "code=?", new String[]{code});
Log.e("HYN", "删除结果" + result);
}
/**
* 更新数据
*
* @param order
*/
public void update(OrderInfo order) {
ContentValues contentValues = new ContentValues();
contentValues.put("code", order.getCode());
contentValues.put("username", order.getUsername());
contentValues.put("state", order.getState());
database.update("pay_order", contentValues, "code=?", new String[]{order.getCode()});
}
/**
* 更新某一个数据根据更新条件(更新一条订单的状态根据订单号)
*
* @param state
* @param code
*/
public void update(String state, String code) {
ContentValues contentValues = new ContentValues();
contentValues.put("state", state);
database.update("pay_order", contentValues, "code=?", new String[]{code});
}
/**
* 查询一条数据根据某一个查询条件
*
* @param code
* @return
*/
public OrderInfo query(String code) {
Cursor cursor = database.query("pay_order", new String[]{"code", "username", "state"}, "code=?", new String[]{code}, null, null, null);
while (cursor.moveToNext()) {
OrderInfo order = new OrderInfo();
order.setCode(cursor.getString(cursor.getColumnIndex("code")));
order.setUsername(cursor.getString(cursor.getColumnIndex("username")));
order.setState(cursor.getString(cursor.getColumnIndex("state")));
return order;
}
return null;
}
/**
* 查询表中所有数据
*
* @return
*/
public List query() {
ArrayList list = new ArrayList<>();
Cursor cursor = database.query("pay_order", null, null, null, null, null, null);
while (cursor.moveToNext()) {
OrderInfo order = new OrderInfo();
order.setCode(cursor.getString(cursor.getColumnIndex("code")));
order.setUsername(cursor.getString(cursor.getColumnIndex("username")));
order.setState(cursor.getString(cursor.getColumnIndex("state")));
list.add(order);
}
cursor.close();
return list;
}
/**
* 删除表
*
* @param table_name
*/
public void delect_table(String table_name) {
//删除表的SQL语句
String sql = "DROP TABLE IF EXISTS" + table_name;
database.execSQL(sql);
}
/**
* 关闭数据库
*/
public void colse() {
database.close();
}
}
实体类OrderInfo
package com.panku.sqlitedemo.db;
/**
* Date:2017/6/13
* Time: 11:57
* author: huangyanan
*/
public class OrderInfo {
private String code;
private String username;
private String state;
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
@Override
public String toString() {
return "code:" + code + "username:" + username + "state:" + state;
}
}
添加权限!添加权限!添加权限!重要的事说三遍