LINQ Query

Level : Intermediate
Mentor: Shailendra Chauhan
Duration : 00:01:00

The Data Source

The data source in ASP.NET Core is the origin of data, typically a database, collection, or external service, from which data is retrieved and manipulated.

Example

var dbContext = new MyDbContext(); // Replace with your DbContext
var data = dbContext.MyEntities;   // Represents the data source

The Query

A query in ASP.NET Core defines a set of operations to retrieve, transform, and filter data from a data source using LINQ (Language-Integrated Query).

Example

var query = from item in data
where item.Price > 50
select item; // Defines a query

Query Execution

Query execution in ASP.NET Core involves invoking the actual data retrieval or processing from the data source, typically triggered by methods like ToList(), First(), or Single().

Example

var result = query.ToList(); // Executes the query and retrieves data

Deferred Execution

In ASP.NET Core, LINQ queries are lazily executed, which means they are not executed until an operation like enumeration or materialization is performed, allowing for optimized performance.

Example

var deferredQuery = data.Where(item => item.Quantity > 10); // Query is not executed here
foreach (var item in deferredQuery) { } // Query is executed when enumerating

Forcing Immediate Execution

To force immediate execution of a query and retrieve results, you can use methods like ToList(), ToArray(), or First().

Example

var immediateQuery = data.Where(item => item.Category == "Electronics").ToList(); // Executes and retrieves data immediately
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