MYear.ODA

简介

C# .Net Database ORM for Oracle DB2 MySql SqlServer SQLite MariaDB;
纯c#开发，支持.NetCore 2.0,.Net standard
MYear.ODA 是一个数据库访问的 ORM 组件，能够通用常用的数据库 DB2、Oracle、SqlServer、MySql(MariaDB)、SQLite; 对不常用的数据库Informix、Sybase、Access也能简单的使用；
就目前而言，MYear.ODA 是支持 SQL 语法最完整的 C# ORM 组件;对于分库分表、或分布式数据库也留有很好的扩展空间。分页、动态添加条件、子查询、无限连接查询、Union、Group by、having、In子查询、Exists、Insert子查询、Import高速导入都不在话下，递归查询、case when、Decode、NullDefault、虚拟字段、数据库function、update 字段运算、表达式等都是 ODA 很有特色的地方。允许用户注入SQL代码段，允许用户自己编写SQL代码等，同时也支持存储过程Procedure(或oracle的包）
由于很多开发者都比较喜欢 Lambda 的直观简单，ODA 的查询也扩展了此功能。

ODA 可以在大型开发团队中，人员水平参差不齐的情况下，提高开发人员效率、规范代码编写方式及减少数据库访问问题。
ODA 的性能、功能、运行稳定性及并发性能都是非常强悍的，比Dapper、EF、SqlSugar都有过之而无不及。
注：已有实际项目应用，且Oracle、Mysql、SqlServer 三个数据库上随意切换，
当然，建表时需要避免各种数据库的关键字及要注意不同数据库对数据记录的大小写敏感问题。

MYear.ODA 语法

ODA使用的是链式编程语法，对SQL语句进行直接映射，所以ODA的编写方式与SQL语法神似，只是把Select、Insert、Update、Delete 后置了。
因为ODA是对SQL语句进行直接映射，本身没有什么转换，不会象EF那样转换太多，造成真正在数据库里执行的SQL语句复杂、性能低下，且难以优化。
使用ODA时如有迷茫之处，基本可以用SQL语句类推出ODA的对应写法，学习以成本极低，也极容易成上手，也不需要象EF那样花很多时间去学习。
ODA为求通用各种数据库，转换出来的SQL都是标准通用的SQL语句；一些常用但数据不兼容的部分，在ODA内部实现（如递归树查询、分页等)。
MYear.ODA以 Select、Insert、Update、Delete、Procedure 方法为最终执行方法，调用这些方法时，ODA 将会把生成的SQL语句发送给数据库运行。

性能测试

在信息管理系统中，业务功能程序不会去追求极致的性能，满足一般的人机交互需求就可以；
但在框架底层或影响全局的程序中(如 ORM 组件、AOP 容器等)，特别是在并发量到达一定规模的时候，我们都会追求极致的性能。
ORM 本身的性能会影响系统整体的性能，而且它的使用方式，可维护性，及对程序开发人员的约束，对系统整体性能有全面的影响。
由于 ORM 对程序的侵入性，不好的ORM会把开发人员带偏，走向万劫不复的深渊，EF就是一个很好的反面教材；
EF本身数据映性能就不好、SQL语句生成速度差，但要算最不靠谱的，应该就是生成出来的SQL语句了。
EF生成的SQL有很多的转换，语句非常复杂，经常走不上索引，还没办法优化，导致这些SQL语句在数据库里头运行的简直就是奇慢无比。
再加上EF、Linq的语法需要花大力气去学，使用起来的开发效率也十分低下，代码难以维护，综合起来就是一个恶梦。
要说 ORM 本身的性能其实是比较其次的（虽然ODA的性非常强悍），但关键是 ORM 不要带偏开发者，
然后就是能够规范访问数据库程序代码，提高程序的可维护性同时也要提高开发效率，支持后续的延申应用（如分库、分表，多数据库混用等），
而且 ORM 应该要做到数据库通，同时也要约束开发者不要去使用某个数据库特有的东西。
这才是 ORM 的追求。

数据映射性

1000000条数据记录，查询出来并转成对应的实体对象。
相较于EF 、Dapper 和 Sqlsugar，ODA 的性能是最好的

读取单条数据记录

Dapper比ODA 略胜一点，但预热时间（第一条）比较长，ODA 比 EF与SqlSugar有很明显的优势;
特别是EF相较其他差了好几倍。

SQL生成性能

Dapper、没有此功能不作对比；EF 语句生成速度，简直不忍直视。ODA 比 Sqlsugar 好几倍。

查询分页

Dapper、没有处功能不作对比；EF 、ODA、Sqlsugar 性能相差无几。

用法示例

连接数据库

// 全局设定
ODAContext.SetODAConfig(DbAType.MsSQL, "server=localhost;database=master;uid=sa;pwd=sa;"); 

// 单个上下文设定
var ctx = new ODAContext(DbAType.MsSQL,"server=localhost;database=master;uid=sa;pwd=sa;");

查询

简单查询

SQL的关键字，在ODA中一般都会有对应的方法或属性。
查询指定的字段，字段别名，数据库函数，ODA中都可以很方便地使用。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
DataTable data = U.Where(U.ColUserAccount == "User1")
       .And(U.ColIsLocked == "N")
       .And(U.ColStatus == "O")
       .And(U.ColEmailAddr.IsNotNull)  
       .Select(U.ColUserAccount, U.ColUserPassword.As("PWD"), U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

SELECT T0.USER_ACCOUNT,
       T0.USER_PASSWORD AS PWD,
       T0.USER_NAME,
       T0.PHONE_NO,
       T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.STATUS = @T3
   AND T0.EMAIL_ADDR IS NOT NULL;

查询默认实体

为简化单表查询转为实体写法，ODA提供 SelectM 方法，返回默认实体数据。
此方法是泛型方法 Select<> 的再次封装，它与调用Select<>是一样的。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
List<SYS_USER> data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColStatus == "O", U.ColEmailAddr.IsNotNull)
               .SelectM(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

SELECT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.STATUS = @T3
   AND T0.EMAIL_ADDR IS NOT NULL;

查询并返回指定实体类型

返回的实体类型可以是任意自定义类型，并不一定是对应数据库的实体.
泛型方法 Select<> 对传入的实体类型没有大多要求，它的可写属性与查询的字段名称一致时将赋值。
实体的属性与查询的字段个数无需一致。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
List<SYS_USER> data = U.Where(U.ColUserAccount == "User1",U.ColIsLocked == "N",U.ColStatus == "O",U.ColEmailAddr.IsNotNull)
               .Select<SYS_USER>(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

SELECT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.STATUS = @T3
   AND T0.EMAIL_ADDR IS NOT NULL;

查询分页

ODAContext ctx = new ODAContext(); 
int total = 0; 
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .SelectM(0,20,out total, U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

SELECT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.EMAIL_ADDR IS NOT NULL;

SELECT COUNT(*) AS TOTAL_RECORD
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T4
   AND T0.IS_LOCKED = @T5
   AND T0.EMAIL_ADDR IS NOT NULL;

查询第一行

很多时候我们查询数据库只需取第一行的数据。ODA为简化应用，提供了查询第一行数据返回动态类型数据的方法。
返回结果是动态类型，按查询的字段名取值即可。

ODAContext ctx = new ODAContext(); 
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .SelectDynamicFirst(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);
            
    string UserName = data.USER_NAME;///属性 USER_NAME 与 ColUserName 的ColumnName一致，如果没有数据则返回null

SELECT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.EMAIL_ADDR IS NOT NULL;

SELECT COUNT(*) AS TOTAL_RECORD
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T4
   AND T0.IS_LOCKED = @T5
   AND T0.EMAIL_ADDR IS NOT NULL;

返回动态数据模型

很多时候为一种查询编写一个实体类，实在是很麻烦。
ODA本身提供了动态类型的返回值，这样对取小量数据的程序来说是很方便的了。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .SelectDynamic(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

string UserName = "";
if (data.Count > 0)
UserName =  data[0].USER_NAME; ///与 ColUserName  的 ColumnName一致.

SELECT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = @T1
   AND T0.IS_LOCKED = @T2
   AND T0.EMAIL_ADDR IS NOT NULL;

去重复 Distinct

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where( U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .Distinct.Select(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);

SELECT DISTINCT T0.USER_ACCOUNT, T0.USER_NAME, T0.PHONE_NO, T0.EMAIL_ADDR
  FROM SYS_USER T0
 WHERE T0.IS_LOCKED = @T1
   AND T0.EMAIL_ADDR IS NOT NULL;

连接查询

ODA支持 InnerJoin、LeftJoin、RightJion，且可以无限的Join。
On 的条件也十分灵活，SQL语句支持的条件方式，ODA基本支持。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var R = ctx.GetCmd<CmdSysRole>();
var UR = ctx.GetCmd<CmdSysUserRole>();

var data = U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O")
    .LeftJoin(R, UR.ColRoleCode == R.ColRoleCode, R.ColStatus == "O")
    .Where(U.ColStatus == "O",R.ColRoleCode == "Administrator")
    .Select<UserDefineModel>(U.ColUserAccount.As("UserAccount"), U.ColUserName.As("UserName"),R.ColRoleCode.As("Role"), R.ColRoleName.As("RoleName"));

SELECT T0.USER_ACCOUNT AS UserAccount,
       T0.USER_NAME    AS UserName,
       T1.ROLE_CODE    AS Role,
       T1.ROLE_NAME    AS RoleName
  FROM SYS_USER T0
 INNER JOIN SYS_USER_ROLE T2
    ON T0.USER_ACCOUNT = T2.USER_ACCOUNT
   AND T2.STATUS = 'O'
 INNER JOIN SYS_ROLE T1
    ON T2.ROLE_CODE = T1.ROLE_CODE
   AND T1.STATUS ='O'
 WHERE T0.STATUS = 'O'
   AND T1.ROLE_CODE = 'Administrator';

简单内连接

内连接有很多人只使用 join , 但对形如 SELECT t1.* FROM TABLE1 T1,TABLE2 T2,TABLE3 T3,TABLE4 这种写法比较陌生，
但个人觉得这种连接的写法比较简单，而且容易阅读。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var R = ctx.GetCmd<CmdSysRole>();
var UR = ctx.GetCmd<CmdSysUserRole>();
var data =  U.ListCmd(UR,R)
    .Where(U.ColUserAccount == UR.ColUserAccount, 
           UR.ColStatus == "O",
           UR.ColRoleCode == R.ColRoleCode,
           R.ColStatus == "O",
           U.ColStatus == "O",
           R.ColRoleCode == "Administrator")
.Select< UserDefineModel>(U.ColUserAccount.As("UserAccount"), U.ColUserName.As("UserName"),U.ColEmailAddr.As("Email"), R.ColRoleCode.As("Role"), R.ColRoleName.As("RoleName"));

SELECT T0.USER_ACCOUNT AS UserAccount,
       T0.USER_NAME    AS UserName,
       T0.EMAIL_ADDR   AS Email,
       T1.ROLE_CODE    AS Role,
       T1.ROLE_NAME    AS RoleName
  FROM SYS_USER T0, SYS_USER_ROLE T2, SYS_ROLE T1
 WHERE T0.USER_ACCOUNT = T2.USER_ACCOUNT
   AND T2.STATUS = @T3
   AND T2.ROLE_CODE = T1.ROLE_CODE
   AND T1.STATUS = @T4
   AND T0.STATUS = @T5
   AND T1.ROLE_CODE = @T6;

嵌套子查询

嵌套子查询需要把一个查询子句转换成视图(ToView方法)，转换成视图之后可以把它视作普通的Cmd使用。
视图里ViewColumns是视图字段的集合。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var R = ctx.GetCmd<CmdSysRole>();
var UR = ctx.GetCmd<CmdSysUserRole>();

var UA = ctx.GetCmd<CmdSysUserAuthorization>();
var RA = ctx.GetCmd<CmdSysRoleAuthorization>();

var Admin = U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O")
    .InnerJoin(R, UR.ColRoleCode == R.ColRoleCode, R.ColStatus == "O")
    .Where(U.ColStatus == "O")
    .ToView(U.ColUserAccount.As("SYS_USER"), U.ColUserName, R.ColRoleCode.As("SYS_ROLE"), R.ColRoleName); ////建立视图

var data =  Admin.InnerJoin(UA, UA.ColUserAccount == Admin.ViewColumns[1],UA.ColIsForbidden == "N")
    .InnerJoin(RA,RA.ColRoleCode == Admin.ViewColumns[2],RA.ColIsForbidden =="N") 
    .Where(Admin.ViewColumns[1] == "张三",
           Admin.ViewColumns[2] == "Administrator"
     ).Select();

SELECT *
  FROM (SELECT T0.USER_ACCOUNT AS SYS_USER,
               T0.USER_NAME,
               T1.ROLE_CODE    AS SYS_ROLE,
               T1.ROLE_NAME
          FROM SYS_USER T0
         INNER JOIN SYS_USER_ROLE T2
            ON T0.USER_ACCOUNT = T2.USER_ACCOUNT
           AND T2.STATUS = 'O'
         INNER JOIN SYS_ROLE T1
            ON T2.ROLE_CODE = T1.ROLE_CODE
           AND T1.STATUS = 'O'
         WHERE T0.STATUS = 'O') T6
 INNER JOIN SYS_USER_AUTHORIZATION T3
    ON T3.USER_ACCOUNT = T6.USER_NAME
   AND T3.IS_FORBIDDEN =  'N'
 INNER JOIN SYS_ROLE_AUTHORIZATION T4
    ON T4.ROLE_CODE = T6.SYS_ROLE
   AND T4.IS_FORBIDDEN = 'N'
 WHERE T6.USER_NAME = '张三'
   AND T6.SYS_ROLE = 'Administrator';

Union UnionAll

Union 语句要求被Union或UnionAll的是视图。要求视图与查询的字段的数据库类型及顺序及数据一致（数据库本身的要求，非ODA要求)。

ODAContext ctx = new ODAContext(); 
var U = ctx.GetCmd<CmdSysUser>(); 
var UR = ctx.GetCmd<CmdSysUserRole>();  
var RA = ctx.GetCmd<CmdSysRoleAuthorization>();
var RS = ctx.GetCmd<CmdSysResource>();

var U1 = ctx.GetCmd<CmdSysUser>();
var UA = ctx.GetCmd<CmdSysUserAuthorization>();
var RS1 = ctx.GetCmd<CmdSysResource>();

U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O")
 .InnerJoin(RA, RA.ColRoleCode == UR.ColRoleCode, RA.ColStatus == "O")
 .InnerJoin(RS, RS.ColId == RA.ColResourceId, RS.ColStatus == "O")
 .Where(U.ColUserAccount == "User1");

U1.InnerJoin(UA, U1.ColUserAccount == UA.ColUserAccount, UA.ColStatus == "O")
  .InnerJoin(RS1, RS1.ColId == UA.ColResourceId , RS1.ColStatus=="O")
  .Where(U1.ColUserAccount == "User1");
 
var data = U.Union(U1.ToView(U1.ColUserAccount, U1.ColUserName, UA.ColIsForbidden,
                RS1.ColId, RS1.ColResourceType, RS1.ColResourceScope, RS1.ColResourceLocation
      )).Select(U.ColUserAccount, U.ColUserName, RA.ColIsForbidden,
                RS.ColId, RS.ColResourceType, RS.ColResourceScope, RS.ColResourceLocation
                );

SELECT T0.USER_ACCOUNT,
       T0.USER_NAME,
       T2.IS_FORBIDDEN,
       T3.ID,
       T3.RESOURCE_TYPE,
       T3.RESOURCE_SCOPE,
       T3.RESOURCE_LOCATION
  FROM SYS_USER T0
 INNER JOIN SYS_USER_ROLE T1
    ON T0.USER_ACCOUNT = T1.USER_ACCOUNT
   AND T1.STATUS = 'O'
 INNER JOIN SYS_ROLE_AUTHORIZATION T2
    ON T2.ROLE_CODE = T1.ROLE_CODE
   AND T2.STATUS = 'O'
 INNER JOIN SYS_RESOURCE T3
    ON T3.ID = T2.RESOURCE_ID
   AND T3.STATUS = 'O'
 WHERE T0.USER_ACCOUNT = 'User1'
UNION
SELECT T4.USER_ACCOUNT,
       T4.USER_NAME,
       T5.IS_FORBIDDEN,
       T6.ID,
       T6.RESOURCE_TYPE,
       T6.RESOURCE_SCOPE,
       T6.RESOURCE_LOCATION
  FROM SYS_USER T4
 INNER JOIN SYS_USER_AUTHORIZATION T5
    ON T4.USER_ACCOUNT = T5.USER_ACCOUNT
   AND T5.STATUS = 'O'
 INNER JOIN SYS_RESOURCE T6
    ON T6.ID = T5.RESOURCE_ID
   AND T6.STATUS = 'O'
 WHERE T4.USER_ACCOUNT = 'User1';

查询排序

OrderbyAsc 或OrderbyDesc 对数据按顺序或倒序排列，先给出的排序条件优先排。 OrderbyAsc 或OrderbyDesc 参数可以是多个字段。

ODAContext ctx = new ODAContext();
var RS = ctx.GetCmd<CmdSysResource>();
var datra = RS.Where(RS.ColResourceType == "WEB", RS.ColStatus == "O")
    .OrderbyDesc(RS.ColResourceIndex)
    .SelectM();

数据库查询条件语法

Join、Where、Having 查询参数：条件之间可用运算符 “|”(Or方法）或“&”(And方法)表明条件与条件之间的关系；“|”和“&”只能用于字段的运算
如同时列出多个条件，则说明SQL语句要同时满足所有条件（即“And”关系）；
Where和Having方法可以多次调用，每调一次SQL语句累加一个条件（And、Or、Groupby、OrderbyAsc、OrderbyDesc方法类同)；
与 Where 方法同等级的 And 方法与 Where 方法是等效的;数据筛选条件可以根据业务情况动态增加；
IS NULL/ IS NOT NULL 条件可由字段直接带出，如：ColEmailAddr.IsNotNull

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var UR = ctx.GetCmd<CmdSysUserRole>();

var data = U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O")
    .Where(U.ColStatus == "O", U.ColEmailAddr.IsNotNull.Or(U.ColEmailAddr == "riwfnsse@163.com"),
    U.ColIsLocked == "N",UR.ColRoleCode.In("Administrator", "Admin", "PowerUser", "User", "Guest")) 
    .Groupby(UR.ColRoleCode)
    .Having(U.ColUserAccount.Count > 2)
    .OrderbyAsc(U.ColUserAccount.Count)
    .Select(U.ColUserAccount.Count.As("USER_COUNT"), UR.ColRoleCode);

//以下写法是等效的，条件可以不断的累加
U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O");
U.Where(U.ColStatus == "O");
U.Where(U.ColEmailAddr.IsNotNull.Or(U.ColEmailAddr == "riwfnsse@163.com"));
U.And(U.ColIsLocked == "N");
U.Where(UR.ColRoleCode.In("Administrator", "Admin", "PowerUser", "User", "Guest"));
U.Groupby(UR.ColRoleCode);
U.Having(U.ColUserAccount.Count > 2);
U.OrderbyAsc(U.ColUserAccount.Count);
data = U.Select(U.ColUserAccount.Count.As("USER_COUNT"), UR.ColRoleCode);

SELECT COUNT(T0.USER_ACCOUNT) AS USER_COUNT, T1.ROLE_CODE
  FROM SYS_USER T0
 INNER JOIN SYS_USER_ROLE T1
    ON T0.USER_ACCOUNT = T1.USER_ACCOUNT
   AND T1.STATUS = 'O'
 WHERE T0.STATUS ='O'
   AND (T0.EMAIL_ADDR IS NOT NULL OR T0.EMAIL_ADDR = 'riwfnsse@163.com')
   AND T0.IS_LOCKED = 'N'
   AND T1.ROLE_CODE IN ('Administrator', 'Admin', 'PowerUser', 'User', 'Guest')
 GROUP BY T1.ROLE_CODE
HAVING COUNT(T0.USER_ACCOUNT) > 2
 ORDER BY COUNT(T0.USER_ACCOUNT) ASC;

分组统计, Groupby Having

Groupby 、Having、OrderbyAsc 方法里支持 Function 运算；
Count、Max、Min、Sum、Upper、Lower等数据库通用的内置函数，已在ODA字段里内置了。
其他函数可以使用 ODA Function 。

 ODAContext ctx = new ODAContext();
 var U = ctx.GetCmd<CmdSysUser>();
 var UR = ctx.GetCmd<CmdSysUserRole>();
 var data = U.InnerJoin(UR, U.ColUserAccount == UR.ColUserAccount, UR.ColStatus == "O")
     .Where(U.ColStatus == "O", UR.ColRoleCode.In("Administrator", "Admin", "PowerUser", "User", "Guest"))
     .Groupby(UR.ColRoleCode)
     .Having(U.ColUserAccount.Count > 2)
     .OrderbyAsc(UR.ColRoleCode,U.ColUserAccount.Count)
     .Select(U.ColUserAccount.Count.As("USER_COUNT"), UR.ColRoleCode);

SELECT COUNT(T0.USER_ACCOUNT) AS USER_COUNT, T1.ROLE_CODE
  FROM SYS_USER T0
 INNER JOIN SYS_USER_ROLE T1
    ON T0.USER_ACCOUNT = T1.USER_ACCOUNT
   AND T1.STATUS = @T2
 WHERE T0.STATUS = @T3
   AND T1.ROLE_CODE IN (@T5_0, @T5_1, @T5_2, @T5_3, @T5_4)
 GROUP BY T1.ROLE_CODE
HAVING COUNT(T0.USER_ACCOUNT) > @T6
 ORDER BY T1.ROLE_CODE ASC, COUNT(T0.USER_ACCOUNT) ASC;

IN/NOT IN 条件

IN/NOT IN 有两个重载，一个是in数组，一个是in子查询

ODAContext ctx = new ODAContext(); 
var RA = ctx.GetCmd<CmdSysRoleAuthorization>();
var RS = ctx.GetCmd<CmdSysResource>(); 
///IN 数组
RA.Where(RA.ColIsForbidden == "N", RA.ColStatus == "O", RA.ColRoleCode.In("Administrator", "Admin", "PowerUser"));

///IN 子查询
var data = RS.Where(RS.ColStatus == "O", RS.ColId.In(RA, RA.ColResourceId)) 
    .SelectM();

SELECT *
  FROM SYS_RESOURCE T1
 WHERE T1.STATUS = @T2
   AND T1.ID IN (SELECT T0.RESOURCE_ID
                   FROM SYS_ROLE_AUTHORIZATION T0
                  WHERE T0.IS_FORBIDDEN = @T4
                    AND T0.STATUS = @T5
                    AND T0.ROLE_CODE IN (@T7_0, @T7_1, @T7_2));

Exists/NOT Exists 子查询

ODAContext ctx = new ODAContext();
var RA = ctx.GetCmd<CmdSysRoleAuthorization>(); 
//Exists 子查询的条件
var RS = ctx.GetCmd<CmdSysResource>();
RA.Where(RA.ColIsForbidden == "N", RA.ColStatus == "O", RA.ColResourceId == RS.ColId); 

var data = RS.Where(RS.ColStatus == "O", RS.Function.Exists(RA, RA.AllColumn)) 
    .SelectM();

SELECT *
  FROM SYS_RESOURCE T1
 WHERE T1.STATUS = @T2
   AND EXISTS (SELECT T0.*
          FROM SYS_ROLE_AUTHORIZATION T0
         WHERE T0.IS_FORBIDDEN = @T3
           AND T0.STATUS = @T4
           AND T0.RESOURCE_ID = T1.ID);

递归查询

ODA 递归查询效果与Oracle的StartWith ConnectBy语句一致。
ODA 处理原理：先以 where 条作查出需要递归筛先的数据，然后在内存中递归筛选。
由于是在内存递归，所以递归使所用到的所有字段必须包含在 Seclect 字段里。
注：ODA 递归性能比 oracle 数据库的 StartWith ConnectBy 差一个等级，但比 SQLServer 的 with as 好一个级等。
递归有深度限制，ODA 限制最大深度是31层。
被递归的原始数据越多性能下降很快，最好保被递归筛选的数在10W条以内

ODAContext ctx = new ODAContext();
////由根向叶子递归 Prior 参数就是递归方向
CmdSysResource RS = ctx.GetCmd<CmdSysResource>();  
var rlt = RS.Where(RS.ColStatus == "O", RS.ColResourceType == "MENU")
    .StartWithConnectBy(RS.ColResourceName.ColumnName + "='根菜单'", RS.ColParentId.ColumnName, RS.ColId.ColumnName, "MENU_PATH", "->", 10)
.Select(RS.ColResourceName.As("MENU_PATH"), RS.ColId, RS.ColParentId, RS.ColResourceName, RS.ColResourceType, RS.ColResourceScope, RS.ColResourceLocation, RS.ColResourceIndex);
           
////由叶子向根递归,Prior 参数就是递归方向
CmdSysResource RS1 = ctx.GetCmd<CmdSysResource>(); 
var rlt1 = RS.Where(RS.ColStatus == "O", RS.ColResourceType == "MENU")
    .StartWithConnectBy(RS.ColResourceName.ColumnName + "='菜单1'", RS.ColId.ColumnName, RS.ColParentId.ColumnName, "MENU_PATH", "<-", 10)
.Select(RS.ColResourceName.As("MENU_PATH"), RS.ColId, RS.ColParentId, RS.ColResourceName, RS.ColResourceType, RS.ColResourceScope, RS.ColResourceLocation, RS.ColResourceIndex);

SELECT T0.RESOURCE_NAME AS MENU_PATH,
       T0.ID,
       T0.PARENT_ID,
       T0.RESOURCE_NAME,
       T0.RESOURCE_TYPE,
       T0.RESOURCE_SCOPE,
       T0.RESOURCE_LOCATION,
       T0.RESOURCE_INDEX
  FROM SYS_RESOURCE T0
 WHERE T0.STATUS = @T4
   AND T0.RESOURCE_TYPE = @T5;

Lambda语法支持

Lambda 语法是由 ODA 原生语法扩展而来的，ODA 使用者也可以自行扩展。
ODA 原生语法是可以无限连接的，但目前 Lambda 语法支持最多九个表的连接查询。

int total = 0;
var data = new ODAContext().GetJoinCmd<CmdSysUser>()
   .InnerJoin<CmdSysUserRole>((u, ur) => u.ColUserAccount == ur.ColUserAccount & ur.ColStatus == "O")
   .InnerJoin<CmdSysRole>((u, ur, r) => ur.ColRoleCode == r.ColRoleCode & r.ColStatus == "O")
   .InnerJoin<CmdSysRoleAuthorization>((u, ur, r, ra) => r.ColRoleCode == ra.ColRoleCode & ra.ColIsForbidden == "O" & ra.ColStatus == "O")
   .Where((u, ur, r, ra) => u.ColStatus == "O" & (r.ColRoleCode == "Administrator" | r.ColRoleCode == "Admin") & u.ColIsLocked == "N")
   .Groupby((u, ur, r, ra) => new IODAColumns[] { r.ColRoleCode, u.ColUserAccount })
   .Having((u, ur, r, ra) => ra.ColResourceId.Count > 10)
   .OrderbyAsc((u, ur, r, ra) => new IODAColumns[] { ra.ColResourceId.Count })
   .Select(0, 20, out total, (u, ur, r, ra) => new IODAColumns[] { r.ColRoleCode, u.ColUserAccount, ra.ColResourceId.Count.As("ResourceCount") });

SELECT T2.ROLE_CODE,
       T0.USER_ACCOUNT,
       COUNT(T3.RESOURCE_ID) AS ResourceCount
  FROM SYS_USER T0
 INNER JOIN SYS_USER_ROLE T1
    ON (T0.USER_ACCOUNT = T1.USER_ACCOUNT AND T1.STATUS = @T4)
 INNER JOIN SYS_ROLE T2
    ON (T1.ROLE_CODE = T2.ROLE_CODE AND T2.STATUS = @T5)
 INNER JOIN SYS_ROLE_AUTHORIZATION T3
    ON (T2.ROLE_CODE = T3.ROLE_CODE AND T3.IS_FORBIDDEN = @T6 AND
       T3.STATUS = @T7)
 WHERE (T0.STATUS = @T8 AND (T2.ROLE_CODE = @T9 OR T2.ROLE_CODE = @T10) AND
       T0.IS_LOCKED = @T11)
 GROUP BY T2.ROLE_CODE, T0.USER_ACCOUNT
HAVING COUNT(T3.RESOURCE_ID) > @T12
 ORDER BY COUNT(T3.RESOURCE_ID) ASC;

SELECT COUNT(*) AS TOTAL_RECORD
  FROM (SELECT T2.ROLE_CODE,
               T0.USER_ACCOUNT,
               COUNT(T3.RESOURCE_ID) AS ResourceCount
          FROM SYS_USER T0
         INNER JOIN SYS_USER_ROLE T1
            ON (T0.USER_ACCOUNT = T1.USER_ACCOUNT AND T1.STATUS = @T15)
         INNER JOIN SYS_ROLE T2
            ON (T1.ROLE_CODE = T2.ROLE_CODE AND T2.STATUS = @T16)
         INNER JOIN SYS_ROLE_AUTHORIZATION T3
            ON (T2.ROLE_CODE = T3.ROLE_CODE AND T3.IS_FORBIDDEN = @T17 AND
               T3.STATUS = @T18)
         WHERE (T0.STATUS = @T19 AND
               (T2.ROLE_CODE = @T20 OR T2.ROLE_CODE = @T21) AND
               T0.IS_LOCKED = @T22)
         GROUP BY T2.ROLE_CODE, T0.USER_ACCOUNT
        HAVING COUNT(T3.RESOURCE_ID) > @T23) T14;

更新数据

通常的 update 方式

Update 语句通常不会更新所有的字段，而是update指定字段。
Update 的 where 条件与查询是语句是一致的。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColStatus == "O", U.ColEmailAddr.IsNotNull)
 .Update(U.ColUserName == "新的名字", U.ColIsLocked == "Y");

 UPDATE SYS_USER
   SET USER_NAME = '新的名字', IS_LOCKED ='Y'
 WHERE USER_ACCOUNT = 'User1'
   AND IS_LOCKED = 'N'
   AND STATUS = 'O'
   AND EMAIL_ADDR IS NOT NULL;

模型数据 Upadte

使用实体 Update 数据时，对于属性值为 null 的字段不作更新。
这是由于在 ORM 组件在实际应用中，多数时候界面回传的是完整的实体对象，
或者收接时使用完整的实体作为反序列化的容器，那些不需要更新的字段也在其中，而且为null。

ODAContext ctx = new ODAContext(); 
var U = ctx.GetCmd<CmdSysUser>();
    U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColStatus == "O", U.ColEmailAddr.IsNotNull)
    .Update(new SYS_USER()
    {
        ADDRESS = "自由国度",
        CREATED_BY = "InsertModel",
        CREATED_DATE = DateTime.Now, 
        STATUS = "O",
        USER_ACCOUNT = "MYear1",
        USER_NAME = "多年1",
        USER_PASSWORD = "123",
        IS_LOCKED = "N",
    });

 UPDATE SYS_USER
   SET STATUS        = 'O',
       CREATED_BY    = 'InsertModel',
       CREATED_DATE  = '2019-03-29',,
       USER_ACCOUNT  = 'MYear1',
       USER_NAME     = '多年1',
       USER_PASSWORD = '123',
       ADDRESS       = '自由国度',
       IS_LOCKED     = 'N'
 WHERE USER_ACCOUNT = 'User1'
   AND IS_LOCKED = 'N'
   AND STATUS = 'O'
   AND EMAIL_ADDR IS NOT NULL;

更新运算

支持的运算符号：+ 、 - 、*、/、% 目前对一个字段更新时，只支持一个运算符号；

ODAContext ctx = new ODAContext(); 
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .Update(U.ColFailTimes == U.ColFailTimes + 1, U.ColUserName == U.ColUserAccount + U.ColEmailAddr );

  UPDATE SYS_USER
   SET FAIL_TIMES = FAIL_TIMES + 1, USER_NAME = USER_ACCOUNT + EMAIL_ADDR
 WHERE USER_ACCOUNT = 'User1'
   AND IS_LOCKED ='N'
   AND EMAIL_ADDR IS NOT NULL;

删除数据

Delete的where条件 SELECT 语句一致

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
   .Delete();

   DELETE FROM SYS_USER T0
 WHERE T0.USER_ACCOUNT = 'User1'
   AND T0.IS_LOCKED = 'N'
   AND T0.EMAIL_ADDR IS NOT NULL;

插入数据据

插入指定字段的数据

没有指下指定的字段，不会出现在SQL语句里。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
U.Insert(U.ColStatus == "O", U.ColCreatedBy == "User1", U.ColLastUpdatedBy == "User1", U.ColLastUpdatedDate == DateTime.Now,
        U.ColCreatedDate == DateTime.Now,U.ColUserAccount == "Nyear", U.ColUserName == "多年", U.ColUserPassword == "123",
        U.ColFeMale == "M", U.ColFailTimes ==0,U.ColIsLocked =="N");

插入模型的数据

对于实体属性值为 null 的字段不作插入。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>(); 
U.Insert(new SYS_USER()
  {
      ADDRESS = "自由国度",
      CREATED_BY = "InsertModel",
      CREATED_DATE = DateTime.Now, 
      FAIL_TIMES = 0,
      STATUS = "O",
      USER_ACCOUNT = "NYear1",
      USER_NAME = "多年1",
      USER_PASSWORD = "123",
      IS_LOCKED ="N",
  });

批量导入数据d

导入 DataTable 数据时，要保证 DataTable 字段类型与数据库对应的字段类型一致。
DB2、Oracle、MsSql、MySql、SQLite都实现了高整导入，比循环插入快好几倍，甚至几十倍。
但对于MySql数据库，因为驱动不支持Blob字段的导入，所以包含Blob字段的表，ODA内部自动识别使用循环插入。

DataTable data = new DataTable();
data.Columns.Add(new DataColumn("ADDRESS"));
data.Columns.Add(new DataColumn("CREATED_BY"));
data.Columns.Add(new DataColumn("CREATED_DATE",typeof(DateTime)));
data.Columns.Add(new DataColumn("EMAIL_ADDR"));
data.Columns.Add(new DataColumn("LAST_UPDATED_BY"));
data.Columns.Add(new DataColumn("LAST_UPDATED_DATE", typeof(DateTime))); 
data.Columns.Add(new DataColumn("FAIL_TIMES", typeof(decimal)));
data.Columns.Add(new DataColumn("STATUS"));
data.Columns.Add(new DataColumn("DUMMY"));
data.Columns.Add(new DataColumn("USER_ACCOUNT"));
data.Columns.Add(new DataColumn("USER_NAME"));
data.Columns.Add(new DataColumn("USER_PASSWORD"));
data.Columns.Add(new DataColumn("IS_LOCKED"));
             
for (int i = 0; i < 10000; i++)
{
    object[] dr = new object[]
    {
        "自由国度",
         "User1" ,
         DateTime.Now,
         "riwfnsse@163.com",
         "User1" ,
         DateTime.Now,
         0,
         "O",
         "Dummy",
         "ImportUser" + i.ToString(),
         "导入的用户" + i.ToString(),
         "123",
         "N"                   
      };
      data.Rows.Add(dr); 
}

 ODAContext ctx = new ODAContext();
 var U = ctx.GetCmd<CmdSysUser>();
 U.Import(data);

事务

ODA 事务的控制管理在 ODAContext 里，每一个 ODAContext 实例同一时间只会开启一个事务。
ODA 事务有默认的超时时间是30秒，用户也可以自己指定一个事务的超时时间。
一般来说，越是大型的系统，数据库资源就越是珍贵，事务的应用就越要谨慎。
能不用事务完成的事情绝不用事务，事务里的DML操作能少一个就少一个，事务运行的时间能少一点就少一点
因为事务锁定的数据库对象，只有在事务完成的时候才能释放，而且同一时间只允许一个用户锁定。
因此事务会降低系统的并发性能，长时间锁定数据库对象，或发生等待锁、死锁等，对系统的影响将是致命的。

  ODAContext ctx = new ODAContext();
  var U1 = ctx.GetCmd<CmdSysUser>();
  ctx.BeginTransaction();
  try
  {
      var U = ctx.GetCmd<CmdSysUser>();
      U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColStatus == "O", U.ColEmailAddr.IsNotNull)
      .Update(U.ColUserName == "新的名字", U.ColIsLocked == "Y"); 
      
      U1.Insert(U.ColStatus == "O", U1.ColCreatedBy == "User1", U1.ColLastUpdatedBy == "User1", U1.ColLastUpdatedDate == DateTime.Now, U1.ColCreatedDate == DateTime.Now,U1.ColUserAccount == "Nyear", U1.ColUserName == "多年", U1.ColUserPassword == "123", U1.ColFeMale == "M", U1.ColFailTimes == 0, U1.ColIsLocked == "N");
      
       ctx.Commit();
   }
   catch
   {
      ctx.RollBack();
   }

函数

数据库函数

ODA提供数据库常用的通用系统函数：MAX, MIN, COUNT, SUM, AVG, LENGTH, LTRIM, RTRIM, TRIM, ASCII, UPPER, LOWER
这些函数由字段直接带出，如：ColUserAccount.Count

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
       .Groupby(U.ColUserAccount)
       .Select(U.Function.Count.As("CountAll"), U.ColUserAccount.Count.As("CountOne"), U.ColUserAccount.Upper.As("UPPER_ACC"), U.ColUserAccount.Trim.Ltrim.As("TRIM_ACC"));

SELECT COUNT(*) AS CountAll,
       COUNT(T0.USER_ACCOUNT) AS CountOne,
       UPPER(T0.USER_ACCOUNT) AS UPPER_ACC,
       LTRIM(T0.USER_ACCOUNT) AS TRIM_ACC
  FROM SYS_USER T0
 WHERE T0.STATUS = 'O'
   AND T0.IS_LOCKED = 'N'
 GROUP BY T0.USER_ACCOUNT;

表达式

Express方法, 用户可在 SELECT 字段中注入自定义的一段SQL脚本。因为ODA 的表达式是开发者注入的一段SQL语句，所以SQL注入的风险及是否可以跨数据库，就用开发者掌握了。

ODAParameter p1 = new ODAParameter() { ColumnName = "Params1", DBDataType = ODAdbType.OVarchar, Direction = System.Data.ParameterDirection.Input, ParamsName = ODAParameter.ODAParamsMark + "Params1", ParamsValue = "我是第一个参数的值", Size = 2000 };
 ODAParameter p2 = new ODAParameter() { ColumnName = "Params2", DBDataType = ODAdbType.OVarchar, Direction = System.Data.ParameterDirection.Input, ParamsName = ODAParameter.ODAParamsMark + "Params2", ParamsValue = "这是SQL语句注入", Size = 2000 };
ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
       .Select(U.Function.Express("1+1").As("COMPUTED"),
        U.Function.Express(" null ").As("NULL_COLUMN"), 
        U.Function.Express(" 'Function( + " + ODAParameter.ODAParamsMark + "Params1, " + ODAParameter.ODAParamsMark + "Params2)' ", p1, p2).As("SQL_Injection"));

SELECT 1 + 1 AS COMPUTED,
       null AS NULL_COLUMN,
       'Function( + @Params1, @Params2)' AS SQL_Injection
  FROM SYS_USER T0
 WHERE T0.STATUS = @T1
   AND T0.IS_LOCKED = @T2;

虚拟字段、临时字段

VisualColumn 方法是对 Express 方法的再次封装，为应用提供方便，免出数据转换麻烦、避免SQL注入风险、保证数据库通用。

 ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
      .Select(U.Function.VisualColumn("HELLO , I am MYear software").As("STRING_COLUMN"), U.Function.VisualColumn(DateTime.Now).As("APPLICATION_DATETIME"), U.Function.VisualColumn(0).As("DIGIT_COLUMN"));

SELECT 'HELLO , I am MYear software' AS STRING_COLUMN,
       @T1 AS APPLICATION_DATETIME,
       0 AS DIGIT_COLUMN
  FROM SYS_USER T0
 WHERE T0.STATUS = 'O'
   AND T0.IS_LOCKED = 'N';

用户自定义的函数

CreateFunc 方法,用可在 SELECT 字段中加入自定义的数据库函数，但不同的数据库对调用自定义函数的方法差异太大，ODA无法将其统一。
所以若要ODA Function.CreateFunc方法也要以跨数据库，则需要在创建数据库时，特殊处理数据库的schema,user,dbowner,database等对象的名称。

ODAContext ctx = new ODAContext();
var RS = ctx.GetCmd<CmdSysResource>();
object data = RS.Where(RS.ColStatus == "O",RS.ColResourceType =="MENU") 
       .Select(RS.AllColumn,RS.Function.CreateFunc("dbo.GET_RESOURCE_PATH", RS.ColId).As("RESOURCE_PATH"));

 SELECT T0.*,dbo.GET_RESOURCE_PATH(T0.ID) AS RESOURCE_PATH 
 FROM SYS_RESOURCE T0 
 WHERE T0.STATUS = 'O' AND T0.RESOURCE_TYPE = 'MENU';

数据内容转换 CaseWhen

SQL 语句： case when 条件 then 值 when 条件 then 值 else 默认值 end

ODAContext ctx = new ODAContext();  
var U = ctx.GetCmd<CmdSysUser>();
Dictionary<ODAColumns, object> Addr = new Dictionary<ODAColumns, object>();
Addr.Add(U.ColAddress.IsNull, "无用户地址数据...");
Addr.Add(U.ColAddress.Like("%公安局%"), "被抓了?");

Dictionary<ODAColumns, object> phone = new Dictionary<ODAColumns, object>();
phone.Add(U.ColPhoneNo.IsNull, "这个家伙很懒什么都没有留下");
phone.Add(U.ColPhoneNo == "110", "小贼快跑");
phone.Add(U.ColAddress.NotLike("%公安局%"), "被抓了?");

object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
       .Select(U.Function.CaseWhen(Addr, U.ColAddress).As("ADDRESS"), U.Function.CaseWhen(phone, "110").As("PHONE_NO"));

 SELECT (CASE
         WHEN T0.ADDRESS IS NULL THEN
          '无用户地址数据...'
         WHEN T0.ADDRESS LIKE '%公安局%' THEN
          '被抓了?'
         ELSE
          T0.ADDRESS
       END) AS ADDRESS,
       (CASE
         WHEN T0.PHONE_NO IS NULL THEN
          '这个家伙很懒什么都没有留下'
         WHEN T0.PHONE_NO = '110' THEN
          '小贼快跑'
         WHEN T0.ADDRESS NOT LIKE '%公安局%' THEN
          '被抓了'
         ELSE
         '110'
       END) AS PHONE_NO
  FROM SYS_USER T0
 WHERE T0.STATUS = 'O'
   AND T0.IS_LOCKED ='N';

空值转换

NullDefault 是对CaseWhen方法的再次封装，以方便应用

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
       .Select(U.Function.NullDefault(U.ColAddress, "无用户地址数据...").As("ADDRESS"), U.Function.NullDefault(U.ColPhoneNo,110).As("PHONE_NO"));

SELECT (CASE
         WHEN T0.ADDRESS IS NULL THEN
          '无用户地址数据...'
         ELSE
          T0.ADDRESS
       END) AS ADDRESS,
       (CASE
         WHEN T0.PHONE_NO IS NULL THEN
          110
         ELSE
          T0.PHONE_NO
       END) AS PHONE_NO
  FROM SYS_USER T0
 WHERE T0.STATUS = 'O'
   AND T0.IS_LOCKED = 'N';

数据内容转换 Case

SQL 语句： case 字段 when 对比值 then 值 when 对比值 then 值 else 默认值 end

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();

Dictionary<object, object> Addr = new Dictionary<object, object>();
Addr.Add(U.Function.Express(" NULL "), "无用户地址数据...");
Addr.Add("天堂", "人生最终的去处");
Dictionary<object, object> phone = new Dictionary<object, object>();
phone.Add(U.Function.Express(" NULL "), "这个家伙很懒什么都没有留下");
phone.Add( "110", "小贼快跑");
phone.Add(U.ColAddress, "资料有误，电话与地址相同");

object data = U.Where(U.ColStatus == "O", U.ColIsLocked == "N")
       .Select(U.Function.Case(U.ColAddress,Addr, U.ColAddress).As("ADDRESS"), U.Function.Case(U.ColPhoneNo,phone, U.ColPhoneNo).As("PHONE_NO"));

SELECT (CASE T0.ADDRESS
         WHEN NULL THEN
          '无用户地址数据...'
         WHEN '天堂' THEN
          '人生最终的去处'
         ELSE
          T0.ADDRESS
       END) AS ADDRESS,
       (CASE T0.PHONE_NO
         WHEN NULL THEN
          '这个家伙很懒什么都没有留下'
         WHEN '110' THEN
          '小贼快跑'
         WHEN T0.ADDRESS THEN
          '资料有误，电话与地址相同'
         ELSE
          T0.PHONE_NO
       END) AS PHONE_NO
  FROM SYS_USER T0
 WHERE T0.STATUS = 'O'
   AND T0.IS_LOCKED = 'N'

数据内容转换Decode

ODA Decode方法模拟Oracle内置Decode函数,对Case方法的再次封装，以方便应用

ODAContext ctx = new ODAContext();
var RS = ctx.GetCmd<CmdSysResource>();
object data = RS.Where(RS.ColStatus == "O", RS.ColResourceType == "MENU")
       .Select(RS.Function.Decode(RS.ColResourceType, "未知类型", "WEB", "网页资源", "WFP_PAGE", "WPF页面资源", "WPF_WIN", "WPF程序窗口", "WIN_FORM", "FORM窗口").As("RESOURCE_TYPE")
                 , RS.AllColumn);

SELECT (CASE T0.RESOURCE_TYPE
         WHEN 'WEB' THEN
          '网页资源'
         WHEN 'WFP_PAGE' THEN
          'WPF页面资源'
         WHEN 'WPF_WIN' THEN
          'WPF程序窗口'
         WHEN 'WIN_FORM' THEN
          'FORM窗口'
         ELSE
          '未知类型'
       END) AS RESOURCE_TYPE,
       T0.*
  FROM SYS_RESOURCE T0
 WHERE T0.STATUS = 'O'
   AND T0.RESOURCE_TYPE = 'MENU';

进阶应用

这里介绍一些在开发过程中不时会遇到的问题，对应有处理方式。

字段的连接

字段的连接，不同数据库的处理差异太大，ODA没有提供字符串连接的方法
但可以用户DataTable方法或通能过实体属性实现

DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("COL_ID", typeof(string)));
dt.Columns.Add(new DataColumn("COL_NUM", typeof(int)));
dt.Columns.Add(new DataColumn("COL_TEST", typeof(string)));
dt.Columns.Add(new DataColumn("COL_NUM2", typeof(int)));
for (int i = 0; i < 100; i++) 
{
   if(i%3==1)
    dt.Rows.Add(Guid.NewGuid().ToString("N").ToUpper(), i + 1, string.Format("this is {0} Rows", i + 1), null);
    else
    dt.Rows.Add(Guid.NewGuid().ToString("N").ToUpper(), i + 1, string.Format("this is {0} Rows", i + 1), 1000);
} 
dt.Columns.Add("CONNECT_COL", typeof(string), "COL_ID+'  +  '+COL_TEST");
dt.Columns.Add("ADD_COL", typeof(decimal), "COL_NUM+COL_NUM2");

Datatable转List

 DataTable data = new DataTable();
 data.Columns.Add(new DataColumn("ADDRESS"));
 data.Columns.Add(new DataColumn("CREATED_BY"));
 data.Columns.Add(new DataColumn("CREATED_DATE", typeof(DateTime)));
 data.Columns.Add(new DataColumn("EMAIL_ADDR"));
 data.Columns.Add(new DataColumn("LAST_UPDATED_BY"));
 data.Columns.Add(new DataColumn("LAST_UPDATED_DATE", typeof(DateTime)));
 data.Columns.Add(new DataColumn("FAIL_TIMES", typeof(decimal)));
 data.Columns.Add(new DataColumn("STATUS"));
 data.Columns.Add(new DataColumn("DUMMY"));
 data.Columns.Add(new DataColumn("USER_ACCOUNT"));
 data.Columns.Add(new DataColumn("USER_NAME"));
 data.Columns.Add(new DataColumn("USER_PASSWORD"));
 data.Columns.Add(new DataColumn("IS_LOCKED"));
 for (int i = 0; i < 10000; i++)
 {
     object[] dr = new object[]
     {
        "自由国度",
        "User1" ,
        DateTime.Now,
        "riwfnsse@163.com",
        "User1" ,
        DateTime.Now,
        0,
        "O",
        "Dummy",
        "ImportUser" + i.ToString(),
        "导入的用户" + i.ToString(),
        "123",
        "N"
      };
    data.Rows.Add(dr);
}
List<SYS_USER> DataList = ODA.DBAccess.ConvertToList<SYS_USER>(data);

自定义SQL

如果SQL语可以重复使用，或者为有程序更规范，推荐派生 ODACmd 类重写SQL生成方法。
ODA 提供一个通用的派生类 SQLCmd ，可执行临时的SQL语句。

ODAContext ctx = new ODAContext();
var sql = ctx.GetCmd<SQLCmd>();
var data = sql.Select("SELECT * FROM SYS_USER WHERE USER_ACCOUNT = @T1", ODAParameter.CreateParam("@T1","User1"));
////可用方法
/// sql.Select<T>(string Sql, params ODAParameter[] Parameters)
/// sql.SelectDynamicFirst(string Sql, params ODAParameter[] Parameters)
/// sql.Update(string Sql, params ODAParameter[] Parameters)
/// sql.Insert(string Sql, params ODAParameter[] Parameters)
/// sql.Delete(string Sql, params ODAParameter[] Parameters)
/// sql.Procedure(string Sql, params ODAParameter[] Parameters)

自定义存储过程

如果SQL语可以重复使用，或者为有程序更规范，推荐派生 ODACmd 类重写SQL生成方法

ODAContext ctx = new ODAContext();
var sql = ctx.GetCmd<SQLCmd>();
var data = sql.Procedure("");

SQL Debug 调试

开发者要查看 ODA 最终执行的 SQL 及其参数值，可以在调试时查看 ODAContext.LastODASQL 静态属性。

ODAContext ctx = new ODAContext();
var U = ctx.GetCmd<CmdSysUser>();
var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
    .SelectDynamicFirst(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr); 
////ODAContext.LastODASQL;属性是ODA最近生成的SQL语句块,包含了ODA 控制SQL语句(并非真正发送给数据库的SQL)、参数、语句类型、操作对象等； 
var ODASQL = ODAContext.LastODASQL;
///ctx.LastSQL属性是最近发送给数据库的SQL；由于分页的方法是两条SQL，所以此处的SQL是最后读取数据库的SQL；
string sql = ctx.LastSQL;
///ctx.SQLParams属性是最近发送给数据库的SQL的参数；
object[] param = ctx.SQLParams;

ODA钩子

如果有数据库有分库分表，ODA 提供的由算法不合适，可通过 ODA 钩子自定义数据库、表的路由
当然用户可以通 ODA 的钩子程序可以监控到所有 ODA 执行的 SQL及其参数，这为业务程序问题定位及日志记录供了一个方便的入口
钩子程序里，无需进行SQL语句分析,就有明确的 SQL 类型，需要访问的表及字段信息供使用。程序这对数据库的操作一清二楚。

public static object Hook()
{
  ///开发者可以通过ODA钩子自定义SQL路由,在SQL执行前对SQL进行修改； 
  ODAContext.CurrentExecutingODASql += ODASqlExecutingEvent; 
  DAContext ctx = new ODAContext();
  var U = ctx.GetCmd<CmdSysUser>();
  var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
     .Select(U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr); 
     ODAContext.CurrentExecutingODASql -= ODASqlExecutingEvent;
     return data;
}

private static void ODASqlExecutingEvent(object source, ExecuteEventArgs args)
{
    if (args.SqlParams.ScriptType == SQLType.Select
      && args.SqlParams.TableList.Contains("SYS_USER"))
    {
       args.DBA = new ODA.Adapter.DbASQLite("Data Source=./sqlite.db"); ///改变ODA预设的数据库执行实例，重新实例化一个SQL语句执行实例。
       args.SqlParams.ParamList.Clear();
       args.SqlParams.SqlScript.Clear();
       args.SqlParams.SqlScript.AppendLine(" SELECT * FROM SYS_ROLE"); ///修改将要执行的SQL语句
    }
} 
  
///SQL语句监控钩子
public static object Monitor()
{
   ///开发者可能通过此钩子，可以监控所有发送给数据库SQL语句及其参数。 
   ODAContext.CurrentExecutingSql += SqlExecutingEvent;
   ODAContext ctx = new ODAContext();
   int total = 0;
   var U = ctx.GetCmd<CmdSysUser>();
   var data = U.Where(U.ColUserAccount == "User1", U.ColIsLocked == "N", U.ColEmailAddr.IsNotNull)
      .Select(0, 20, out total, U.ColUserAccount, U.ColUserName, U.ColPhoneNo, U.ColEmailAddr);
    ODAContext.CurrentExecutingSql -= SqlExecutingEvent;
    return data;
}
private static void SqlExecutingEvent(string Sql, object[] prms)
{
    ///记录将要被执行的SQL语句及其参数
    string LogSql = Sql + prms.ToString();  
}

ODA开发工具应用

ODA 提供三个工具：

第一个当然是 ODA 的代码生成工具了，它生成 ODA 需要的实体类及命令类。

第二个是一个简单的 SQL 语句执行工具，可以执行简单的 SQL 语句，对SQLite 等缺少 UI 操作工具的数据库来说是比较实用的。

第三个是数据库复制工具，能够在不同数据库之间复制表数据。

Name		Name	Last commit message	Last commit date
Latest commit History 28 Commits
MYear.Demo		MYear.Demo
MYear.ODA.DevTool		MYear.ODA.DevTool
MYear.ODA		MYear.ODA
MYear.PerformanceTest		MYear.PerformanceTest
Reference		Reference
.gitignore		.gitignore
LICENSE		LICENSE
MYear.sln		MYear.sln
README.md		README.md

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MYear.ODA

简介

MYear.ODA 语法

性能测试

数据映射性

读取单条数据记录

SQL生成性能

查询分页

用法示例

连接数据库

查询

简单查询

查询默认实体

查询并返回指定实体类型

查询分页

查询第一行

返回动态数据模型

去重复 Distinct

连接查询

简单内连接

嵌套子查询

Union UnionAll

查询排序

数据库查询条件语法

分组统计, Groupby Having

IN/NOT IN 条件

Exists/NOT Exists 子查询

递归查询

Lambda语法支持

更新数据

通常的 update 方式

模型数据 Upadte

更新运算

删除数据

插入数据据

插入指定字段的数据

插入模型的数据

批量导入数据d

事务

函数

数据库函数

表达式

虚拟字段、临时字段

用户自定义的函数

数据内容转换 CaseWhen

空值转换

数据内容转换 Case

数据内容转换Decode

进阶应用

字段的连接

Datatable转List

自定义SQL

自定义存储过程

SQL Debug 调试

ODA钩子

ODA开发工具应用

ODA 提供三个工具：

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