postgreSQL的crud操作详解

​ //命令行操作
​ createdb database_name;
​ CREATE DATABASE database_name;
psql -l  //展示所有数据库
psql database_name //进入数据库

​ dropdb database;
​ DROP DATABASE database_name;

​ create table 表名 (title varchar(255), content text);
//修改表名
alter table posts rename to 表名;

//查看表信息(结构)
\d 表名
//执行这个sql文件
\i a.sql
//切换数据显示方式（横向和纵向显示） 
\x 

create table posts (
  id serial primary key,
  title varchar(255) not null,
  content text check(length(content) > 3),
  is_draft boolean default FALSE,
  created_date timestamp default 'now');

CREATE TABLE public.students
(
 id integer NOT NULL,
 name character(128),
 subjects character(1),
 CONSTRAINT student2_pkey PRIMARY KEY (id)
)
WITH (
 OIDS=FALSE
);
ALTER TABLE public.students
 OWNER TO postgres;
COMMENT ON TABLE public.students
 IS '这是一个学生信息表';

​ DROP TABLE students;

insert into 表名(cloum1,cloum2) value(a,b);

//分页查询limit和offset结合使用。 
select * from users order by score desc limit 3;
select * from users order by score desc limit 3 offset 3;

select team,max(score) from users group by team having max(score)>25 order by max(score);

 select player,length(player) from users;
 select player,concat(player,"/",team) from users;
 select player,concat(player,"/",team) as "球员信息" from users;
 select concat('我',substring(team,1,1)) as "球队首文字" from users;
 //随机抽奖
 select player from users order by random() limit 1;

update [table] set [field=newvalue,…] where …
delete from [table] where …

 update users set score = score + 100 where team IN ("勇士","骑士");

//alter table [tablename] …
//给表添加一条fullname字段
alter table users add fullname varchar(255);

//给哪个表的字段建索引(索引提高查询效率，但是增删效果不好)
create index 索引名 on users(字段名);
//删除索引
drop index 索引名;

//修改列名
alter table users rename player to nba_player;
//修改字段的的长度
alter table users alter nba_player type varchar(128);

//两表的关联查询
select users.player,twitters.content from users,twitters where users.id = twitters.user_id;
//别名
select u.player,t.content from users as u,twitters as t where u.id = t.user_id;

//创建一个视图(通过 \dv 查看视图描述)
create view curry_twitters as select u.player,t.content from users as u,twitters as t where u.id = t.user_id;
//要进行查询时
select * from curry_twitters;
//删除视图
drop view curry_twitters; 

eg：
begin;
update users set score = 50 where player = '库里';
update users set score = 60 where player = '哈登';
commit; //如果不想跟新可以 rollback;

/******************************************************************
* 表名：test3
* Made by 码农下的天桥
******************************************************************/
--use MYDB;--你可以指定自己的数据库
/******************************************************************
****************************各种常用查询***************************
******************************************************************/
------------------------------------
--用途：复杂形式的查询语句，用于查询分页数据。
--这个是泛用型的，假如你要根据用户输入去查询，那么最好不要用这个了，
--以免出现sql注入。
--参数说明：
---_offset int 需要取的记录的开始位置
---_limit int 需要获取记录的总条数，针对分页而言，就是分页的pagesize。
---_columns varchar(800) 需要获取的字段
---_where varchar(800) 需要过滤的条件譬如： where id<10 可以带where，不过建议不要带。
---_orderby varchar(800) 需要进行排序的提交，譬如：order by id
---_totalCount int 返回总共记录条数。
---_totalPages int 返回总共页数。
------------------------------------
create or replace function test3_getListByCondition(
INOUT pageindex INT,
INOUT pagesize INT,
IN _columns VARCHAR(800),
IN _where VARCHAR(800),
IN _orderby VARCHAR(800),
out _totalCount INT,
out _totalPages INT)
returns SETOF record
AS
$$
DECLARE condition_columns VARCHAR(800);
DECLARE condition_where varchar(800);
DECLARE condition_orderby VARCHAR(800);
DECLARE _dymatic_sql VARCHAR(1600);
DECLARE _beginNO INT;
DECLARE _dynamic_getCount varchar(1600);
DECLARE _theOffset INT;
DECLARE _tmpInt1 INT;
BEGIN
condition_where:=ltrim(rtrim(COALESCE(_where,'')));
condition_orderby:=ltrim(rtrim(COALESCE(_orderby,'order by t3id')));
condition_columns:=ltrim(rtrim(COALESCE(_columns,'*')));
--分析传过来的参数，构造动态sql语句。
IF "character_length"(condition_where)>0 THEN
IF strpos(condition_where, 'where ')!=1 THEN
condition_where:='where ' || condition_where;
END IF;
END IF;
--order by 语句构造
IF "character_length"(condition_orderby)>0 THEN
IF strpos(condition_orderby, 'order ')!=1 THEN
condition_orderby:='order by '||condition_orderby;
END IF;
END IF;
 
--判断pageindex是否合法及pagesize是否合法
IF pageindex<1 THEN
pageindex:=1;
END IF;
IF pagesize<1 THEN
pagesize:=20;
END IF;
 
_dynamic_getCount:='select count(*) from test3 '||condition_where|| ' ' ;
EXECUTE _dynamic_getCount INTO _totalCount;
IF _totalCount<1 THEN
pageindex:=1;
RETURN;
END IF;
--计算总共页数
_tmpInt1:=_totalCount%pagesize;
IF _tmpInt1=0 THEN
_totalPages:=_totalCount / pagesize;
ELSE
_totalPages:=(_totalCount-_tmpInt1)/pagesize+1;
END IF;
IF _totalPages < pageindex then
pageindex:=_totalPages;
END IF;
_theOffset:=(pageindex-1) * pagesize+1;
_dymatic_sql:='select '||condition_columns||' from test3 '||condition_where||' '||condition_orderby||' limit '||pagesize||' '|| ' offset '||_theOffset||' ';
--raise info '动态构造语句为：%',_dymatic_sql;
return query EXECUTE _dymatic_sql;
END;
$$ language plpgsql VOLATILE;
------------------------------------
--用途：复杂形式的查询语句，用于查询多条记录数据。
--这个是泛用型的，假如你要根据用户输入去查询，那么最好不要用这个了，
--以免出现sql注入。
--参数说明：
---_offset int 需要取的记录的开始位置
---_limit int 需要获取记录的总条数，针对分页而言，就是分页的pagesize。
---_columns varchar(800) 需要获取的字段
---_where varchar(800) 需要过滤的条件譬如： where id<10 可以带where，不过建议不要带。
---_orderby varchar(800) 需要进行排序的提交，譬如：order by id
---_totalCount int 返回总共记录条数。
------------------------------------
create or replace function test3_getPageByCondition(
INOUT pageindex INT,
INOUT pagesize INT,
IN _columns VARCHAR(800),
IN _where VARCHAR(800),
IN _orderby VARCHAR(800),
out _totalCount INT,
out _totalPages INT,
out _refcursor refcursor
)
returns SETOF record
AS
$$
DECLARE condition_columns VARCHAR(800);
DECLARE condition_where varchar(800);
DECLARE condition_orderby VARCHAR(800);
DECLARE _dymatic_sql VARCHAR(1600);
DECLARE _beginNO INT;
DECLARE _dynamic_getCount varchar(1600);
DECLARE _theOffset INT;
DECLARE _tmpInt1 INT;
BEGIN
condition_where:=ltrim(rtrim(COALESCE(_where,'')));
condition_orderby:=ltrim(rtrim(COALESCE(_orderby,'order by t3id')));
condition_columns:=ltrim(rtrim(COALESCE(_columns,'*')));
--分析传过来的参数，构造动态sql语句。
IF "character_length"(condition_where)>0 THEN
IF strpos(condition_where, 'where ')!=1 THEN
condition_where:='where ' || condition_where;
END IF;
END IF;
--order by 语句构造
IF "character_length"(condition_orderby)>0 THEN
IF strpos(condition_orderby, 'order ')!=1 THEN
condition_orderby:='order by '||condition_orderby;
END IF;
END IF;
--判断pageindex是否合法及pagesize是否合法
IF pageindex<1 THEN
pageindex:=1;
END IF;
IF pagesize<1 THEN
pagesize:=20;
END IF;
_dynamic_getCount:='select count(*) from test3 '||condition_where|| ' ' ;
EXECUTE _dynamic_getCount INTO _totalCount;
IF _totalCount<1 THEN
pageindex:=1;
RETURN;
END IF;
--计算总共页数
_tmpInt1:=_totalCount%pagesize;
IF _tmpInt1=0 THEN
_totalPages:=_totalCount / pagesize;
ELSE
_totalPages:=(_totalCount-_tmpInt1)/pagesize+1;
END IF;
IF _totalPages < pageindex then
pageindex:=_totalPages;
END IF;
_theOffset:=(pageindex-1) * pagesize+1;
_dymatic_sql:='select '||condition_columns||' from test3 '||condition_where||' '||condition_orderby||' limit '||pagesize||' '|| ' offset '||_theOffset||' ';
--raise info '动态构造语句为：%',_dymatic_sql;
open _refcursor for EXECUTE _dymatic_sql;
RETURN NEXT;
END;
$$ language plpgsql VOLATILE;
------------------------------------
--用途：获取其中一条记录
------------------------------------
create or replace function test3_getRecord(in _id integer)
returns SETOF test3
AS
$$
BEGIN
return query select * from test3 where t3id=_id LIMIT 1 OFFSET 0;
END;
$$ LANGUAGE plpgsql VOLATILE;
------------------------------------
--用途：复杂形式的查询语句，用于查询前面第几条记录，这个就相当好了
--这个是泛用型的，假如你要根据用户输入去查询，那么最好不要用这个了，
--以免出现sql注入。
--参数说明：
---_topN int 需要取的topN条记录。
---_columns varchar(800) 需要获取的字段
---_where varchar(800) 需要过滤的条件譬如： where id<10 可以带where，不过建议不要带。
---_orderby varchar(800) 需要进行排序的提交，譬如：order by id
------------------------------------
create or replace function test3_getTopNbyCondition(IN _topN int,IN _columns VARCHAR(800),IN _where VARCHAR(800),IN _orderby VARCHAR(800))
returns SETOF test3
AS
$$
DECLARE condition_columns VARCHAR(800);
DECLARE condition_where varchar(800);
DECLARE condition_orderby VARCHAR(800);
DECLARE _dymatic_sql VARCHAR(1600);
BEGIN
condition_where:=ltrim(rtrim(COALESCE(_where,'')));
condition_orderby:=ltrim(rtrim(COALESCE(_orderby,'order by t3id')));
condition_columns:=ltrim(rtrim(COALESCE(_columns,'*')));
--分析传过来的参数，构造动态sql语句。
IF "character_length"(condition_where)>0 THEN
IF strpos(condition_where, 'where ')!=1 THEN
condition_where:='where ' || condition_where;
END IF;
END IF;
--order by 语句构造
IF "character_length"(condition_orderby)>0 THEN
IF strpos(condition_orderby, 'order ')!=1 THEN
condition_orderby:='order by '||condition_orderby;
END IF;
END IF;
_dymatic_sql:='select '||condition_columns||' from test2 '||condition_where||' '||condition_orderby||' limit '||CAST(_topN as VARCHAR)|| ' offset 0 ';
--raise info '动态构造语句为：%',_dymatic_sql;
return query EXECUTE _dymatic_sql;
END;
$$ language plpgsql VOLATILE;
/******************************************************************
*****************************记录删除******************************
******************************************************************/
------------------------------------
--用途：删除多条记录
------------------------------------
create or replace function test3_DeleteList(in ids VARCHAR(800),out status boolean,out msg VARCHAR(200))
returns record
AS
$$
DECLARE _arr_ids int[];
DECLARE _str_ids "text";
DECLARE _str_sql VARCHAR(1600);
DECLARE _effects int;
BEGIN
IF "character_length"(ids)<1 THEN
status:=false;
msg:='没有指定需要删除的数据！';
return;
end if;
_arr_ids:=tools_str2intarray(ids, ',');
_str_ids:=tools_stringify(_arr_ids,',');
--pkey为主键，自增的整数， <@ 表示判断pkey是不是在数组里面。是不是很方便？
/*动态构造执行*/
--_str_sql:='DELETE FROM test3 where t3id in ('||_str_ids||') ;';
--EXECUTE _str_sql;
/*直接执行*/
delete from test3 where t3id =ANY( _arr_ids);
GET DIAGNOSTICS _effects = ROW_COUNT;
IF _effects>0 THEN
status:=true;
msg:='成功删除'||_effects||'条记录！';
ELSE
status:=false;
msg:='没有删除任何记录！';
end if;
 
END
$$ LANGUAGE plpgsql VOLATILE; 
 
/******************************************************************
****************************添加及编辑*****************************
******************************************************************/
 
------------------------------------
--用途：增加一条记录
------------------------------------
 
create or replace function test3_Insert(
       in __t3name varchar(400) ,
       in __t_birthday date ,
       in __myage smallint ,
       in __isadmin boolean ,
       in __myintro text ,
       in __price float ,
 out __t3id integer,
out _status boolean,
out _msg varchar(200))
returns record AS $$
BEGIN
             
Insert into test3
(
"t3name","t_birthday","myage","isadmin","myintro","price"
)
values(
__t3name,__t_birthday,__myage,__isadmin,__myintro,__price
);
/*判断添加记录是否成功。*/
if FOUND then
_status:=true;
_msg:='成功添加记录.';
__t3id:=currval(pg_get_serial_sequence('test3', 't3id'));
else
_status:=false;
_msg:='无法添加记录!';
end if;
end;
$$ LANGUAGE plpgsql VOLATILE;
 
------------------------------------
--用途：修改一条记录
------------------------------------
create or replace function test3_Update(
       in __t3name varchar(400) ,
       in __t_birthday date ,
       in __myage smallint ,
       in __isadmin boolean ,
       in __myintro text ,
       in __price float ,
 in __t3id integer,
out _status boolean,
out _msg varchar(200))
returns record AS $$
BEGIN             
 
update test3 set
"t3name"=__t3name,"t_birthday"=__t_birthday,"myage"=__myage,"isadmin"=__isadmin,"myintro"=__myintro,"price"=__price where t3id=__t3id;
/*判断保存记录是否成功。*/
if FOUND then
_status:=true;
_msg:='成功保存记录.';
else
_status:=false;
_msg:='无法保存记录!';
end if;
end;
$$ LANGUAGE plpgsql VOLATILE;

package EasisWeb.DAL;
 
import EasisWeb.config.DBPool;
import Easis.Common.StringUtil;
import Easis.util.DataRow;
import Easis.util.DataTable;
import Easis.util.DataTableHelper;
import java.util.Date;
import Easis.DBUtility.PooledConnection;
import java.sql.*;
import java.util.List;
import java.util.ArrayList;
import Easis.util.OperationResult;
import Easis.util.PagerResult;
import EasisWeb.Model.test3Model;
/**
* 这是利用CodeGen工具生成的自动访问数据库的一个模板，作者为“码农下的天桥”
*生成的类名称：
* @author 码农下的天桥
* @version 1.00
*/
public class test3DAL {
 
/*表格各种column*/
public static final String col_t3id="test3";
public static final String col_t3name="test3";
public static final String col_t_birthday="test3";
public static final String col_myage="test3";
public static final String col_isadmin="test3";
public static final String col_myintro="test3";
public static final String col_price="test3";
public static final String PKColumn="t3id"; 
 
/**
*存储过程名称：test3_ListByCondition
*存储过程参数：
*@param pageindex
*@param pagesize
*@param columns   需要获取的字段
*@param condition  where条件语句
*@param orderColumn  order by排序语句
*
*@return 分页对象
*/
 
public PagerResult getPageListByCondition(int pageindex,int pagesize, String columns, String condition, String orderColumn){
PagerResult pres=new PagerResult();
//output参数定义
int _total = 0 ;
int _pagesize = 0 ;
int _pageindex = 0 ;
int _totalpages = 0 ;
//output参数定义结束
//调用存储过程
DataTable res__datatable=new DataTable();
try{
PooledConnection __myconn=DBPool.getConnection();
__myconn.setAutoCommit(false); // return refcursor must within a transaction
CallableStatement _stmt=__myconn.prepareCall("{ call test3_getPageByCondition( ?, ?, ?, ?, ?, ?, ?, ?)}");
_stmt.setInt(1,pageindex);
_stmt.setInt(2,pagesize);
_stmt.registerOutParameter(1,Types.INTEGER);
_stmt.registerOutParameter(2,Types.INTEGER);
_stmt.setString(3,columns);
_stmt.setString(4,condition);
_stmt.setString(5,orderColumn);
_stmt.registerOutParameter(6, Types.INTEGER);
_stmt.registerOutParameter(7, Types.INTEGER);
_stmt.registerOutParameter(8,Types.OTHER);
_stmt.execute();
ResultSet __rslist=(ResultSet)_stmt.getObject(8);
res__datatable=DataTableHelper.rs2datatable(__rslist);
//取回参数
_total=_stmt.getInt(6);
pres.totalrecords=_total;
_pageindex=_stmt.getInt(1);
pres.totalrecords=_total;
_pagesize=_stmt.getInt(2);
pres.pageindex=_pageindex;
pres.pagesize=_pagesize;
_totalpages=_stmt.getInt(7);
pres.totalpages=_totalpages;
pres.datasource=res__datatable;
//--提交并还原
__myconn.commit();
__myconn.setAutoCommit(true); //返回游标必须在一个事务中，提交完以后将autocommit还原。
//释放资源
__rslist.close();
_stmt.close();
__myconn.close();}
catch (Exception __e){
System.out.println("在运行[test3DAL]的List_Condition时候出现错误。");
__e.printStackTrace();
}
return pres;
}
 
/**
*存储过程名称：test3_Insert
*存储过程参数：
*param t3id 【主键】
    t3name
    t_birthday
    myage
    isadmin
    myintro
    price
 *
*@return
*/
public OperationResult Insert(test3Model model){
OperationResult __ores=new OperationResult();
/*output参数定义*/
int t3id = 0 ;
DataRow returnInfo=new DataRow();
boolean status = false ;
String message = "" ;
/*output参数定义结束*/
/*调用存储过程*/
 
try{
PooledConnection __myconn=DBPool.getConnection();
             CallableStatement _stmt=__myconn.prepareCall("{call test3_Insert(?,?,?,?,?,?,?,?,?)}");
 
      _stmt.setObject(1,model.t3name,Types.VARCHAR);
        _stmt.setObject(2,new Timestamp(model.t_birthday.getTime()),Types.DATE);
        _stmt.setObject(3,model.myage,Types.SMALLINT);
        _stmt.setObject(4,model.isadmin,Types.BOOLEAN);
        _stmt.setObject(5,model.myintro,Types.VARCHAR);
        _stmt.setObject(6,model.price,Types.FLOAT);
   _stmt.registerOutParameter(7,Types.INTEGER,-1);
_stmt.registerOutParameter(8, Types.BOOLEAN,1);
_stmt.registerOutParameter(9, Types.VARCHAR,200);
_stmt.execute();
 
/*取回参数*/
t3id=_stmt.getInt(7);
status=_stmt.getBoolean(8);
message=_stmt.getString(9);
 
__ores.id= t3id;
__ores.status=status;
__ores.message=message;
/*释放资源*/
 
_stmt.close();
__myconn.close();}
catch (Exception __e){
__e.printStackTrace();
__ores.message=__e.toString();
}
return __ores;
}
 
/**
*存储过程名称：test3_Update
*存储过程参数：
* t3id【主键】
    t3name
    t_birthday
    myage
    isadmin
    myintro
    price
 *
*@return
*/
public OperationResult Update(test3Model model){
OperationResult __ores=new OperationResult();
/*output参数定义*/
boolean status = false ;
String message = "" ;
/*output参数定义结束*/
/*调用存储过程*/
DataTable res__datatable=new DataTable();
try{
PooledConnection __myconn=DBPool.getConnection();
CallableStatement _stmt=__myconn.prepareCall("{ call test3_Update( ?,?,?,?,?,?,?,?,?)}");
 
 
      _stmt.setObject(1,model.t3name,Types.VARCHAR);
        _stmt.setObject(2,new Timestamp(model.t_birthday.getTime()),Types.DATE);
        _stmt.setObject(3,model.myage,Types.SMALLINT);
        _stmt.setObject(4,model.isadmin,Types.BOOLEAN);
        _stmt.setObject(5,model.myintro,Types.VARCHAR);
        _stmt.setObject(6,model.price,Types.FLOAT);
   _stmt.setInt(7,model.t3id);
_stmt.registerOutParameter(8, Types.BOOLEAN,1);
_stmt.registerOutParameter(9, Types.VARCHAR,400);
_stmt.execute();
/*取回参数*/
status=_stmt.getBoolean(8);
message=_stmt.getString(9);
 
__ores.status=status;
__ores.message=message;
 
/*释放资源*/
 
_stmt.close();
__myconn.close();}
catch (Exception __e){
__e.printStackTrace();
}
return __ores;
}
 
/**
*存储过程名称：test3_DeleteList
*存储过程参数：
*@param ids    【参数名称：ids    参数类型:nvarchar 对应java类型：String 长度:400   】
*
*@return
*/
public OperationResult DeleteList( String ids){
/*output参数定义*/
OperationResult __ores=new OperationResult();
boolean status = false ;
String message = "" ;
/*output参数定义结束*/
/*调用存储过程*/
DataTable res__datatable=new DataTable();
try{
PooledConnection __myconn=DBPool.getConnection();
CallableStatement _stmt=__myconn.prepareCall("{ call test3_DeleteList( ?, ?, ?)}");
 
_stmt.setString(1,ids); 
_stmt.registerOutParameter(2, Types.BOOLEAN,1); 
_stmt.registerOutParameter(3, Types.VARCHAR,400);
_stmt.execute();
/*取回参数*/
status=_stmt.getBoolean(2);
message=_stmt.getString(3);
 
__ores.status=status;
__ores.message=message;
/*释放资源*/
 
_stmt.close();
__myconn.close();}
catch (Exception __e){
__e.printStackTrace();
}
return __ores;
}
 
/**
*存储过程名称：test3_GetRecord
*存储过程参数：
*@param t3id   【参数名称：id    参数类型:int  对应java类型：int  长度:非字符类型 】
*
*@return DataTable对象。
*/
 
public test3Model GetRecord( int t3id ){
/*调用存储过程*/
DataTable res__datatable=new DataTable();
test3Model model=new test3Model();
try{
PooledConnection __myconn=DBPool.getConnection();
CallableStatement _stmt=__myconn.prepareCall("{ call test3_GetRecord( ?)}");
 
_stmt.setInt(1,t3id);
ResultSet __rslist =_stmt.executeQuery();
res__datatable=DataTableHelper.rs2datatable(__rslist);
model=tryParseModel(res__datatable.get(0));
 
/*释放资源*/
__rslist.close();
_stmt.close();
__myconn.close();}
catch (Exception __e){
__e.printStackTrace();
}
 
return model;
}
 
/**
*存储过程名称：test3_Top_Condition
*存储过程参数：
*@param topN   【参数名称：topN   参数类型:int  对应java类型：int  长度:非字符类型 】
*@param columns   【参数名称：columns   参数类型:nvarchar 对应java类型：String 长度:800   】
*@param condition  【参数名称：condition  参数类型:nvarchar 对应java类型：String 长度:800   】
*@param orderColumn  【参数名称：orderColumn  参数类型:nvarchar 对应java类型：String 长度:800   】
*
*@return DataTable对象。
*/
public DataTable Top_Condition( int topN, String columns, String condition, String orderColumn ){
/*调用存储过程*/
DataTable res__datatable=new DataTable();
try{
PooledConnection __myconn=DBPool.getConnection();
CallableStatement _stmt=__myconn.prepareCall("{ call test3_Top_Condition( ?, ?, ?, ?)}");
 
_stmt.setInt(1,topN);
 
_stmt.setString(2,columns);
 
_stmt.setString(3,condition);
 
_stmt.setString(4,orderColumn);
ResultSet __rslist =_stmt.executeQuery();
res__datatable=DataTableHelper.rs2datatable(__rslist);
 
/*释放资源*/
__rslist.close();
_stmt.close();
__myconn.close();}
catch (Exception __e){
__e.printStackTrace();
}
 
return res__datatable;
}
 
public test3Model tryParseModel(DataRow drow){
test3Model model=new test3Model();
if(drow==null){
return model;
}
 
/*
return "boolean";
return "Date";
return "double";
return "float";
return "int";
return "long";
return "String";
return "Object";
*/
 
/*尝试赋值*/
  model.t3id = drow.get("t3id").toInt();
   model.t3name = drow.get("t3name").toString();
   model.t_birthday = drow.get("t_birthday").toDate();
   model.myage = drow.get("myage").toInt();
   model.isadmin = drow.get("isadmin").toBoolean();
   model.myintro = drow.get("myintro").toString();
   model.price = drow.get("price").toFloat();
 return model;
}
 
public List<test3Model> tryParseList(List<DataRow> dataList){
 List<test3Model> modellist=new ArrayList<test3Model>();
  if(dataList==null){
  return modellist;
  }
 
  for(DataRow drow :dataList){
  modellist.add(tryParseModel(drow));
  }
 
  return modellist;
  }
}