Thursday, 1 August 2013

LINQ Basics

LINQ (Language Integrated Query, pronounced "link") is a Microsoft .NET Framework component that adds native data querying.)

Linq is the Microsoft's first attempt to integrate queries into language. We know, it is really easy to find data from sql objects simply writing a query while its somewhat hectic when we want to do the same thing in a DataTable or Lists. Generally we will have to loop through every elements to find the exact match, if there is some aggregation we need to aggregate the values etc. Linq provides an easy way to write queries that can run with the in memory objects.

Linq provides an easy way to write queries that can run with the in memory objects.

Example: (from item in itemlist where item.value = somevalue select item).toList();

Types of LINQ

    Linq comes with 3 basic types (Provided there are lots of more types of LINQ on different type of objects :

  1. LINQ (Linq to Objects)

    Linq To Objects - examine System.Linq.Enumerable for query methods. These target IEnumerable, allowing any typed loopable collection to be queried in a type-safe manner. These queries rely on compiled .Net methods, not Expressions.

  2. DLINQ (Linq to SQL)
  3. XLINQ (Linq to XML)

LINQ Operators

  • Restriction Operator
  • Projection Operator
  • Partition Operators
    Take, Skip, TakeWhile, SkipWhile
  • Ordering Operators
    OrderBy, OrderByDescending, ThenBy, ThenByDescending, Reverse
  • Grouping Operators
  • Set Operators
    Distinct, Union, Intersect, Except
  • Conversion Operators
    ToArray, ToList, ToDictionary, OfType
  • Element Operators
    First, FirstOrDefault, ElementAt
  • Generation Operators
    Range, Repeat
  • Quantifiers
    Any, All
  • Aggregate Operators
    Count, Sum, Min, Max, Average, Aggregate
  • Miscellaneous Operators
    Concat, EquallAll
  • Custom Sequence Operators
  • Query Execution
    Deferred, Immediate, Query Reuse
  • Join Operators
    Cross Join, Group Join, Cross Join with Group Join, Left Ounter join

101 LINQ Samples

LINQ to Objects

What is Language-Integrated Query - LINQ?

LINQ Query Expressions

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