Linq. pdf

LINQ to SQL Full name: Based on relational data .NET Language integration query , Used to manage relational data in the form of objects , and
Provides rich query functions .
Linq in where Query and SQL In the command Where The effect is similar , They all play the role of limiting the scope, that is, filtering
Of , And the judging condition is the following clause .

One 、LINQ The basic syntax of contains the following 8 Context keywords , These keywords and specific descriptions are as follows ：

Two 、LINQ in where Inquire about
where Clause , It is LINQ Element filtering mechanism of expression , Except for the beginning and the end , It can almost appear
stay LINQ Anywhere in the expression .
In a LINQ Expression , There can be where Clause , There can be no ; There can be one , There can be more than one ; many
individual where The logical relationship between clauses is equivalent to logic “ And ”, Every where Clauses can contain 1 One or more
bool Logical expression , These conditions become predicates , Predicate logic is used between “&&”“||” Wait instead of SQL in
Of and 、or.
Two 、LINQ in where Inquire about
where Clause , It is LINQ Element filtering mechanism of expression , Except for the beginning and the end , It can almost appear
stay LINQ Anywhere in the expression .
In a LINQ Expression , There can be where Clause , There can be no ; There can be one , There can be more than one ; many
individual where The logical relationship between clauses is equivalent to logic “ And ”, Every where Clauses can contain 1 One or more
bool Logical expression , These conditions become predicates , Predicate logic is used between “&&”“||” Wait instead of SQL in
Of and 、or.