Query difference

Question

Hi, What is the difference between comprehensive queries and lamba queries in linq.

Vulpes · Answer

Lambda queries use the LINQ extension methods directly. These methods take lambda expressions as argumemts. For example: string[] names = {"Pip", "Squeak", "Wilfred"}; IEnumerable query = names.Where(n => n.Contains("i")).Select (n => n.ToLower()); foreach(string s in query) Console.WriteLine(s); // output pip wilfred Query comprehensions use a special syntax which looks a bit like SQL but with the 'select' clause at the end rather than the beginning: IEnumerable query2 = from name in names where name.Contains("i") select name.ToLower(); foreach(string s in query2) Console.WriteLine(s); produces the same output as the lambda query above to which it is equivalent.

Jignesh Trivedi · Answer

comprehensive queries Feature... Transparently query multiple databases in one expression e.g. a Microsoft Access Database and an SQL Server Database Translates function calls and property accessors in the String, DateTime and Nullable`1 classes that have SQL equivalents e.g. firstName.Length, firstName.ToUpper(), orderDate.Year, shippedDate.HasValue etc. Does not use MARS - Multiple Active Result Sets, an SQL Server 2005 specific feature Lambda query A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. All lambda expressions use the lambda operator =>, which is read as "goes to". The left side of the lambda operator specifies the input parameters (if any) and the right side holds the expression or statement block. The lambda expression x => x * x is read "x goes to x times x." This expression can be assigned to a delegate type. example : my table structure as below. Customer ==> Address ==> Contact. comprehensive query. from c in ctx.Contacts where c.Address.CustomerID = 123 and select c Lambda Query. Customers . Where ( c => c . Id == 3 ). Select ( c => c . Addresses . Select ( a => a . Contacts ). FirstOrDefault ()). FirstOrDefault () you may also refer : http://msdn.microsoft.com/en-us/library/bb308959.aspx hope this help.

Aarti · Answer

Lambda: Lambda expressions are the natural evolution of anonymous methods : Func filter = delegate (string s) { return s.Length == 5; }; Func extract = delegate (string s) { return s; }; Func project = delegate (string s) { return s.ToUpper(); }; IEnumerable query = names.Where(filter) .OrderBy(extract) .Select(project); for more refer this link: http://msdn.microsoft.com Thanks...

Query difference

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