MyDAL - .FirstOrDefaultAsync() 使用
索引：
一.api 列表
.firstordefaultasync()
.firstordefaultasync<m>()
如: .firstordefaultasync<agent>() , 用于 单表/多表连接 查询.
.firstordefaultasync<vm>()
如: .firstordefaultasync<agentvm>() , 用于 单表 查询.
.firstordefaultasync<t>(expression<func<m, t>> columnmapfunc)
如: .firstordefaultasync<guid>(it => it.id) , 用于 单表 单列 查询.
或者:
.firstordefaultasync<agentvm>(it => new agentvm
{
xxxx = it.name,
yyyy = it.pathid
}) , 用于 单表 多列 查询.
.firstordefaultasync<t>(expression<func<t>> columnmapfunc)
如: .queryer<agent, agentinventoryrecord>(out var agent, out var agentrecord)
......
.firstordefaultasync<string>(() => agent.name)
用于 多表连接 单列 查询.
或者:
.queryer<agent, agentinventoryrecord>(out var agent2, out var record2)
......
.firstordefaultasync(() => new agentvm
{
nn = agent2.pathid,
yy = record2.id,
xx = agent2.id,
zz = agent2.name,
mm = record2.lockedcount
}) , 用于 多表连接 多列 查询.
二.api 单表-便捷 方法 举例
1. 单表 单列 便捷方法
1 var pk = guid.parse("8f2cbb64-8356-4482-88ee-016558c05b2d");
2 var date= datetime.parse("2018-08-20 19:12:05.933786");
3
4 var res3 = await conn
5 .firstordefaultasync<alipaypaymentrecord, guid>(it => it.id == pk && it.createdon == date,it=>it.id);
生成 sql 如下
1 select `id` 2 from `alipaypaymentrecord` 3 where ( `id`=@id__2 && `createdon`=@createdon__3) 4 order by `createdon` desc 5 limit 0,1;
2. 单表 多列 便捷方法
1 var pk = guid.parse("8f2cbb64-8356-4482-88ee-016558c05b2d");
2 var date= datetime.parse("2018-08-20 19:12:05.933786");
3
4 var res4 = await conn
.firstordefaultasync<alipaypaymentrecord, alipaypaymentrecordvm>(it => it.id == pk && it.createdon == date,
5 it => new alipaypaymentrecordvm
6 {
7 id = it.id,
8 totalamount = it.totalamount,
9 description = it.description
10 });
生成 sql 如下
1 select `id` as id, 2 `totalamount` as totalamount, 3 `description` as description 4 from `alipaypaymentrecord` 5 where ( `id`=@id__2 && `createdon`=@createdon__3) 6 order by `createdon` desc 7 limit 0,1;
3. 单表 单条 vm 便捷方法
1 var pk = guid.parse("8f2cbb64-8356-4482-88ee-016558c05b2d");
2 var date = datetime.parse("2018-08-20 19:12:05.933786");
3
4 var res5 = await conn
5 .firstordefaultasync<alipaypaymentrecord, alipaypaymentrecordvm>(it => it.id == pk && it.createdon == date);
生成 sql 如下
1 select `id`, 2 `createdon`, 3 `totalamount`, 4 `description`, 5 `canceledon` 6 from `alipaypaymentrecord` 7 where ( `id`=@id__2 && `createdon`=@createdon__3) 8 order by `createdon` desc 9 limit 0,1;
4. 单表 单条 m 便捷方法
1 var pk = guid.parse("8f2cbb64-8356-4482-88ee-016558c05b2d");
2 var date = datetime.parse("2018-08-20 19:12:05.933786");
3
4 var res6 = await conn
5 .firstordefaultasync<alipaypaymentrecord>(it => it.id == pk && it.createdon == date);
生成 sql 如下
1 select * 2 from `alipaypaymentrecord` 3 where ( `id`=@id__2 && `createdon`=@createdon__3) 4 order by `createdon` desc 5 limit 0,1;
三.api 单表-完整 方法 举例
1. 单表 单列 完整方法
1 var time1 = datetime.parse("2018-08-16 19:22:01.716307");
2
3 var res1 = await conn
4 .queryer<agent>()
5 .where(it => it.createdon == time1)
6 .firstordefaultasync<guid>(it => it.id);
生成 sql 如下
1 select `id` 2 from `agent` 3 where `createdon`=@createdon__1 4 order by `createdon` desc 5 limit 0,1;
2.单表 多列 完整方法
1 var res3 = await conn
2 .queryer<agent>()
3 .where(it => it.id == guid.parse("000c1569-a6f7-4140-89a7-0165443b5a4b"))
4 .firstordefaultasync<agentvm>(it => new agentvm
5 {
6 xxxx = it.name,
7 yyyy = it.pathid
8 });
生成 sql 如下
1 select `name` as xxxx, 2 `pathid` as yyyy 3 from `agent` 4 where `id`=@id__1 5 order by `createdon` desc 6 limit 0,1;
3.单表 单条 vm 完整方法
1 var res1 = await conn
2 .queryer<agent>()
3 .where(it => it.id == guid.parse("000c1569-a6f7-4140-89a7-0165443b5a4b"))
4 .firstordefaultasync<agentvm>();
生成 sql 如下
1 select `id`, 2 `createdon`, 3 `userid`, 4 `pathid`, 5 `name`, 6 `phone` 7 from `agent` 8 where `id`=@id__1 9 order by `createdon` desc 10 limit 0,1;
4.单表 单条 m 完整方法
1 var res1 = await conn
2 .queryer<bodyfitrecord>()
3 .where(it => it.id == guid.parse("1fbd8a41-c75b-45c0-9186-016544284e2e"))
4 .firstordefaultasync();
生成 sql 如下
1 select * 2 from `bodyfitrecord` 3 where `id`=@id__1 4 order by `createdon` desc 5 limit 0,1;
四.api 多表连接-完整 方法 举例
1.多表连接 单列 完整方法
1 var res1 = await conn 2 .queryer<agent, agentinventoryrecord>(out var agent, out var agentrecord) 3 .from(() => agent) 4 .innerjoin(() => agentrecord) 5 .on(() => agent.id == agentrecord.agentid) 6 .where(() => agent.agentlevel == agentlevel.distiagent) 7 .firstordefaultasync<string>(() => agent.name);
生成 sql 如下
1 select agent.`name` 2 from `agent` as agent 3 inner join agentinventoryrecord as agentrecord 4 on agent.`id`=agentrecord.`agentid` 5 where agent.`agentlevel`=@agentlevel__4 6 order by agent.`createdon` desc 7 limit 0,1;
2.多表连接 多列 完整方法
1 var guid2 = guid.parse("544b9053-322e-4857-89a0-0165443dcbef");
2
3 var res2 = await conn
4 .queryer<agent, agentinventoryrecord>(out var agent2, out var record2)
5 .from(() => agent2)
6 .innerjoin(() => record2)
7 .on(() => agent2.id == record2.agentid)
8 .where(() => agent2.id == guid2)
9 .firstordefaultasync(() => new agentvm
10 {
11 nn = agent2.pathid,
12 yy = record2.id,
13 xx = agent2.id,
14 zz = agent2.name,
15 mm = record2.lockedcount
16 });
生成 sql 如下
1 select agent2.`pathid` as nn, 2 record2.`id` as yy, 3 agent2.`id` as xx, 4 agent2.`name` as zz, 5 record2.`lockedcount` as mm 6 from `agent` as agent2 7 inner join agentinventoryrecord as record2 8 on agent2.`id`=record2.`agentid` 9 where agent2.`id`=@id__4 10 order by agent2.`createdon` desc 11 limit 0,1;
3.多表连接 单条 m 完整方法
1 var guid6 = guid.parse("544b9053-322e-4857-89a0-0165443dcbef");
2
3 var res6 = await conn
4 .queryer<agent, agentinventoryrecord>(out var agent6, out var record6)
5 .from(() => agent6)
6 .innerjoin(() => record6)
7 .on(() => agent6.id == record6.agentid)
8 .where(() => agent6.id == guid6)
9 .firstordefaultasync<agent>();
生成 sql 如下
1 select agent6.`*` 2 from `agent` as agent6 3 inner join agentinventoryrecord as record6 4 on agent6.`id`=record6.`agentid` 5 where agent6.`id`=@id__4 6 order by agent6.`createdon` desc 7 limit 0,1;
蒙
2018-12-13 14:35 周四
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