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DbContextFactory. AddDataSource ( new DataSource( )
{
Default = true ,
Name = " mysql" ,
ConnectionFacotry = ( ) => new MySql. Data. MySqlClient. MySqlConnection( " server=localhost;user id=root;password=1024;database=test;" ) ,
DatasourceType = DatasourceType. MYSQL,
UseProxy = true //use static proxy,for logger
} ) ;
IDbContext context = null ;
try
{
context = DbContextFactory. GetDbContext ( ) ;
//because set "id[isIdentity=true]",so not set "id" value
var row1 = context. From < Student > ( ) . Insert ( new Student( )
{
Grade = Grade. A,
CreateTime = DateTime. Now,
Name = " jack" ,
} ) ;
//batch added
var row2 = context. From < Student > ( ) . Insert ( new List < Student > ( )
{
new Student( )
{
Grade = Grade. C,
CreateTime = DateTime. Now,
Name = " tom" ,
} ,
new Student( )
{
Grade = Grade. F,
CreateTime = DateTime. Now,
Name = " jar" ,
} ,
} ) ;
}
catch ( Exception e )
{
//debug sql logger
Console. WriteLine ( context. Loggers) ;
}
finally
{
context. Close ( ) ;
}
using ( var context = DbContextFactory. GetDbContext ( ) )
{
//param
var age = 20 ;
DateTime? time = null ;
var sid = 1 ;
//subquery
var subquery = new SubQuery < School > ( )
. Where ( a => a. Id == sid )
. Select ( s => s. Name ) ;
var row1 = context. From < Student > ( )
. Set ( a => a. Age , a => a. Age + age )
. Set ( a => a. Name , subquery)
. Set ( a => a. CreateTime , time, time != null )
. Where ( a => a. Id == 16 )
. Update ( ) ;
//function
context. From < Student > ( )
. Set ( a => a. Name , a => MysqlFun. REPLACE ( a. Name, " a" , " b" ) )
. Where ( a => a. Id == 14 )
. Update ( ) ;
//lock
var student = context. From < Student > ( )
. Where ( a => a. Id == 16 )
. Single ( ) ;
var row2 = context. From < Student > ( )
. Set ( a => a. Age , 80 )
. Set ( a => a. Version , Guid. NewGuid ( ) . ToString ( ) )
. Where ( a => a. Id == 16 && a. Version == student. Version )
. Update ( ) ;
//entity
var row3 = context. From < Student > ( )
. Filter ( a => a. SchoolId )
. Update ( new Student( )
{
Id = 2 ,
CreateTime = DateTime. Now
} ) ;
using ( var context = DbContextFactory. GetDbContext ( ) )
{
var row1 = context. From < Student > ( )
. Where ( a => a. Id == 16 )
. Delete ( ) ;
var subquery = new SubQuery < School > ( )
. Where ( a => a. Id >= 0 )
. Select ( a => a. Id ) ;
var row2 = context. From < Student > ( )
. Where ( a => Operator. In ( a. Id, subquery) )
. Delete ( ) ;
}
IDbContext dbContext = null ;
try
{
dbContext = DbContextFactory. GetDbContext ( ) ;
dbContext. Open ( true ) ;
dbContext. From < Student > ( ) . Insert ( new Student( )
{
Name = " stduent1"
} ) ;
//throw new Exception("rollback");
dbContext. From < School > ( ) . Insert ( new School( )
{
Name = " school1"
} ) ;
dbContext. Commit ( ) ;
}
catch ( Exception )
{
dbContext? . Rollback( ) ;
throw ;
}
finally
{
dbContext? . Close( ) ;
}
//single
var student = context. From < Student > ( )
. Where ( a => a. Id == 19 )
. Single ( ) ;
//subquery
var id = 0 ;
var age = 50 ;
var subquery = new SubQuery < School > ( )
. Where ( a => a. Id >= id )
. Select ( a => a. Id ) ;
//Verify that subquery parameters are written to the current query
var students2 = context. From < Student > ( )
. OrderBy ( a => a. Age )
. Where ( a => a. Id >= Operator. Any ( subquery) && a. Age > age )
. Select ( ) ;
//Partial columns
var students3 = context. From < Student > ( )
. Select ( s => new
{
s. Id,
s. Age
} ) ;
var students = context. From < Student > ( )
. GroupBy ( a => a. Age )
. Having ( a => MysqlFun. Count ( 1L ) > 2 )
. Select ( s => new
{
Count = MysqlFun. Count ( 1L ) ,
s. Age,
} ) ;
var param = new Student( )
{
Name = " zs" ,
Grade = Grade. B,
SchoolId = null ,
Id = null ,
Type = 5
} ;
//Multiple Where Connections with AND
var students = context. From < Student > ( )
. Where ( a => a. Id == param. Id , param. Id != null )
. Where ( a => Operator. Contains ( a. Name, param. Name) , param. Name != null )
. Where ( a => a. Grade == param. Grade , param. Grade != null )
. Where ( a => a. Id > 2 || a. Age < 80 , param. Type == 5 )
. Select ( ) ;
var students2 = context. From < Student > ( )
. Where ( a => a. Id == param. Id , param. Id != null )
. Where ( a => a. Grade == param. Grade , param. Grade != null )
. Where ( a => Operator. StartsWith ( a. Name, param. Name) , param. Name != null )
. Where ( a => a. Id > 2 || a. Age > 20 , param. Type == 8 )
. Select ( ) ;
var students = context. From < Student > ( )
. Page ( 1 , 10 , out long total)
. Select ( ) ;
var students = context. From < Student , School > ( )
. Join ( ( a , b ) => a. SchoolId == b. Id)
. Select ( ( a , b ) => new
{
a. Id,
StuName = a. Name,
SchName = b. Name
} ) ;
//limit 0,10
var students1 = context. From < Student > ( )
. Take ( 10 )
. Select ( ) ;
//limit 10,20
var students2 = context. From < Student > ( )
. Skip ( 10 , 20 )
. Select ( ) ;
//Calling functions in expressions is not recommended, but n-tier attribute access is supported
var student3 = context. From < Student > ( )
. Where ( a => a. CreateTime == DateTime. Now. Date )
. Select ( ) ;
//lock
var students4 = context. From < Student > ( )
. With ( LockType. FOR_UPADTE)
. Select ( ) ;
//exists1
var flag1 = context. From < Student > ( )
. Where ( a => a. Id > 50 )
. Exists ( ) ;
//exists2
var subquery = new SubQuery < School > ( )
. Where ( a => a. Id >= 2 )
. Select ( a => a. Id ) ;
var flag2 = context. From < Student > ( )
. Where ( a => Operator. Exists ( subquery) )
. Count ( ) ;
//count
var count = context. From < Student > ( )
. Where ( a => a. Id > 50 )
. Count ( ) ;
//sum
var sum = context. From < Student > ( )
. Where ( a => a. Id > 50 )
. Sum ( s => s. Id * s. Age ) ;
//distinct
var disinct = context. From < Student > ( )
. Distinct ( )
. Select ( s => s. Name ) ;
public static class MysqlFun
{
[ Function ]
public static string REPLACE ( string column , string oldstr , string newstr )
{
return string . Empty;
}
[ Function ]
public static T Count < T > ( T column )
{
return default ;
}
}
var students = context. From < Student > ( )
. GroupBy ( a => a. Age )
. Having ( a => MysqlFun. Count ( 1L ) > 2 )
. Select ( s => new
{
Count = MysqlFun. Count ( 1L ) ,
s. Age,
} ) ;
var prefix = " @" ;
var values = new Dictionary < string , object > ( ) ;
Expression < Func < Student , bool > > expression = s => s. Age> 40 ;
var expression = ExpressionUtil. BuildExpression ( item, expression, prefix) ;
DEMO.1 Case When Then Else
//Dapper.common doesn't care how you implement it, it only concerns the result of build.
public class Case < T > : ISqlBuilder
{
private List < Expression > _whens = new List < Expression > ( ) ;
private List < string > _thens = new List < string > ( ) ;
string _else = null ;
public string Build ( Dictionary < string , object > values , string prefix )
{
var sb = new StringBuilder( ) ;
foreach ( var item in _whens)
{
var express = ExpressionUtil. BuildExpression ( item, values, prefix) ;
sb. AppendFormat ( " WHEN {0} THEN '{1}'" , express, _thens[ _whens. IndexOf ( item) ] ) ;
}
if ( _else != null )
{
sb. AppendFormat ( " ELSE '{0}'" , _else) ;
}
return string . Format ( " (CASE {0} END)" , sb) ;
}
public static implicit operator string ( Case < T > d ) => string . Empty;
public Case < T > When ( Expression < Func < T , bool > > expression )
{
new Dictionary < string , object > ( ) ;
_whens. Add ( expression) ;
return this ;
}
public Case < T > Then ( string value )
{
_thens. Add ( value) ;
return this ;
}
public Case < T > Else ( string value )
{
_else = value ;
return this ;
}
}
//case
var caseWhen = new Case < Student > ( )
. When ( a => a. Age <= 18 )
. Then ( " children" )
. When ( a => a. Age <= 40 )
. Then ( " Youth" )
. Else ( " Old" ) ;
//The "caseWhen" object is still an ISqlBuild instance at run time, not a string
//The engine passes in parameters and calls the "caseWhen.Build" method of the instance
var students1 = context. From < Student > ( )
. Where ( a => caseWhen == " Old" || caseWhen == " Youth" )
. Select ( s => new
{
s. Id,
GroupAge = ( string ) caseWhen
} ) ;
public class DateAdd < T > : ISqlBuilder
{
public string Column { get ; set ; }
public int Expr { get ; set ; }
public string Unit { get ; set ; }
public Dictionary < string , object > Values { get ; set ; }
public string Build ( Dictionary < string , object > values , string prefix )
{
return " DATE_ADD(" + Column + " ,INTERVAL " + Expr + " " + Unit + " )" ;
}
public DateAdd ( Expression < Func < T , DateTime? > > column , int expr , string unit )
{
this . Column = ExpressionUtil. BuildColumn ( column, null , null ) . FirstOrDefault ( ) . Value;
this . Expr = expr ;
this . Unit = unit ;
}
public static bool operator < ( DateTime? t1 , DateAdd < T > t2 )
{
return false ;
}
public static bool operator < ( DateAdd < T > t1 , DateTime? t2 )
{
return false ;
}
public static bool operator > ( DateTime? t1 , DateAdd < T > t2 )
{
return false ;
}
public static bool operator > ( DateAdd < T > t1 , DateTime? t2 )
{
return false ;
}
public static explicit operator DateTime( DateAdd < T > d ) => DateTime. Now;
}
var adddayfun = new DateAdd < Student > ( a => a. CreateTime , 1 , " day" ) ;
//in columus
var student1 = context. From < Student > ( )
. Select ( s => new
{
s. Id,
DateTime = ( DateTime ) adddayfun //just for type inference
} ) ;
//in expression
var student2 = context. From < Student > ( )
. Where ( a => adddayfun > DateTime. Now )
. Select ( ) ;
public class WinFun < T > : ISqlBuilder
{
string _partition { get ; set ; }
string _orderby { get ; set ; }
private string _methodName { get ; set ; }
public WinFun < T > ROW_NUMBER ( )
{
_methodName = nameof( ROW_NUMBER) ;
return this ;
}
public WinFun < T > PARTITION < TResult > ( Expression < Func < T , TResult > > columns )
{
var cls = ExpressionUtil. BuildColumns ( columns, null , null ) ;
_partition += string . Join ( " ," , cls. Select ( s => s. Value ) ) ;
return this ;
}
public WinFun < T > ORDERBY < TResult > ( Expression < Func < T , TResult > > columns , bool asc = true )
{
var cls = ExpressionUtil. BuildColumns ( columns, null , null ) ;
_orderby += string . Join ( " ," , cls. Select ( s => s. Value ) ) ;
_orderby += ! asc ? " DESC" : " ASC" ;
return this ;
}
/*If there are no parameters in the expression, there is no need to build in build-method*/
public string Build ( Dictionary < string , object > values , string prefix )
{
if ( _methodName == nameof( ROW_NUMBER) )
{
return string . Format ( " ROW_NUMBER()OVER(ORDER BY {0})" , _orderby) ;
}
throw new NotImplementedException( ) ;
}
public static implicit operator ulong ( WinFun < T > d ) => 0 ;
}
var winFun = new WinFun < Student > ( )
. ORDERBY ( a => a. Age )
. ROW_NUMBER ( ) ;
var student1 = context. From < Student > ( )
. Select ( s => new
{
s. Id,
s. Name,
s. Age,
RowNum = ( ulong ) winFun
} ) ;
public class SubQuery < T > : ISubQuery where T : class
{
private Expression _where { get ; set ; }
private Expression _column { get ; set ; }
private string _method { get ; set ; }
private bool _useSignTable = true ;
public string Build ( Dictionary < string , object > values , string prefix )
{
var table = EntityUtil. GetTable < T > ( ) ;
var column = ExpressionUtil. BuildColumn ( _column, values, prefix) . SingleOrDefault ( ) . Value;
var where = ExpressionUtil. BuildExpression ( _where, values, prefix, _useSignTable) ;
if ( _method == nameof( this . Select) )
{
return string . Format ( " (select {0} from {1} where {2})" , column, table. TableName, where ) ;
}
if ( _method == nameof( this . Count) )
{
return string . Format ( " (select count({0}) from {1} where {2})" , column, table. TableName, where ) ;
}
throw new NotImplementedException( ) ;
}
public SubQuery < T > Where ( Expression < Func < T , bool > > expression )
{
_where = expression ;
return this ;
}
public SubQuery < T > Where < T1 , T2 > ( Expression < Func < T1 , T2 , bool > > expression )
{
_useSignTable = false ;
_where = expression ;
return this ;
}
public SubQuery < T > Select < TResut > ( Expression < Func < T , TResut > > expression )
{
_method = nameof( this . Select) ;
_column = expression ;
return this ;
}
public SubQuery < T > Count < TResut > ( Expression < Func < T , TResut > > expression )
{
_method = nameof( this . Count) ;
_column = expression ;
return this ;
}
public override bool Equals ( object obj )
{
return obj is SubQuery < T > query &&
EqualityComparer < Expression > . Default. Equals ( _where, query. _where) &&
EqualityComparer < Expression > . Default. Equals ( _column, query. _column) &&
_method == query. _method;
}
public override int GetHashCode ( )
{
return HashCode. Combine ( _where, _column, _method) ;
}
public static bool operator < ( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static bool operator == ( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static bool operator != ( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static bool operator <=( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static bool operator >=( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static bool operator > ( object t1 , SubQuery < T > t2 )
{
return false ;
}
public static explicit operator string ( SubQuery < T > v ) => string . Empty;
}
//in where
var subquery1 = new SubQuery < Student > ( )
. Where ( a => a. Id <= 15 )
. Select ( s => s. Age ) ;
var student1 = context. From < Student > ( )
. Where ( a=> a. Age>=Operator. Any ( subquery1) )
. Select ( ) ;
//in columns
var subquery2 = new SubQuery < School > ( )
. Where < Student , School > ( ( a , b ) => a. SchoolId== b. Id)
. Select ( s => s. Name ) ;
var student2 = context. From < Student > ( )
. Select ( s=> new
{
s. Id,
StudentName = s. Name,
SchoolName = ( string ) subquery2//just for build
} ) ;