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An Overview Of LINQ

Synopsis
  • Introduction
  • Syntax
  • Advantages
  • Types
  • Operators
Introduction about LINQ
 
LINQ Stands for Language Integrated query which is used to access memory objects, Databases and XML documents and so on.
 
LINQ is designed by Anders Hejlsberg and it is introduced by Visual Studio 2008.
 
Syntax 
 
Lambda Expression
 
Var Val = value. Where (Val<=5);
 
Query Syntax
 
Var Val = from val in Value Where val> 10;
 
Advantages
  • It offers Syntax Highlighting to find out errors during Design time.
  • Write queries easily
  • Development time is reduced.
  • Easy debugging
  • Transformation of data from one to another easily like SQL to XML
Types of LINQ
  • LINQ to objects
  • LINQ to SQL(DLINQ)
  • LINQ to dataset
  • LINQ to XML(XLINQ)
  • LINQ to entities
LINQ Query Operators
 
Query operators are identified based on their functionalities.
  • Filtering Operators
  • Join Operators
  • Projection Operations
  • Sorting Operators
  • Grouping Operators
  • Conversions
  • Concatenation
  • Aggregation
  • Quantifier Operations
  • Partition Operations
  • Generation Operations
  • Set Operations
  • Equality
  • Element Operators
Let us discuss these operators in detail.
 
Filtering Operators
 
Used to select (or) filter particular object based on the condition.
 
The Operators used for filter is,
  • Where
  • ofType
Join Operators
 
Based on the query condition the Join operators are used to join the row or column of the particular tables.
 
The Operators used for Join is,
  • join – join two matching key values
  • GroupJoin – join key values and grouping that two matching values
Projection Operations
 
Project values show the values of particular specific keys.
 
The Operators used for Projection is,
  • Select
  • SelectMany
Sorting Operators
 
It allows us to arrange the elements based on the sequence
 
The Operators used for Sorting are,
  • OrderBy
  • OrderByDescending
  • ThenBy
  • ThenByDescending\
  • Reverse
Grouping Operators
 
It is used to group the values based on a common attribute.
 
The Operators used for Grouping are,
  • GroupBy
  • ToLookup
Conversions
 
It is used to change the type of the Input.
 
The Operators used for Conversion  are,
  • AsEnumerable
  • AsQueryable
  • Cast
  • OfType
  • ToArray
  • ToDictionary
  • ToList
  • ToLookup
Concatenation
 
It is used to unite two values.
 
The Operators used for Concatenation are,
  • Concat
Aggregation
 
It is used to Aggregate (or) grouping (or) or for retrieving the sum of values.
 
The Operators used for Aggregation is,
  • Aggregate
  • Average
  • Count
  • LonCount
  • Max
  • Min
  • Sum
Quantifier Operations
 
This is used to return Boolean Values that are True or False.
 
The Operators used for Quantifier are,
  • All
  • Any
  • Contains
Partition Operators
 
It is used to divide the input sections into two separate sequences and return them.
 
The Operators used for Partition are,
  • Skip
  • SkipWhile
  • Take
  • TakeWhile
Generation Operations
 
New sequence values created.
 
The Operators used for Generation are,
  • DefaultIfEmpty
  • Empty
  • Range
  • Repeat
Set Operations
 
Getting the result based on the criteria.
 
The Operators used for Set Operation are,
  • Distinct
  • Except
  • Intersect
  • Union
Equality
 
It is used to compare two values and find whether those values are an exact match or not.
 
The Operators used for Equality are,
  • SequenceEqual
Element Operators
 
The Operators used for Element are,
  • ElementAt
  • ElementAtOrDefault
  • First
  • FirstOrDefault
  • Last
  • LastOrDefault
  • Single
  • SingleOrDefult
  • DefaultIfEmpty
We will discuss the types of LINQ in my next article. Thanks.
 
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