Reading-Notes

LINQ & Delegates

This topic is important to me because I want to be able to perform SQL like queries directly on collections like arrays, lists, and DB’s.

Retrospective 9

References

LINQ

Intro to LINQ Queries

Basic LINQ Query Operations

Walkthrough Writing LINQ Queries

LINQ

• Overview
  • Language Integrated Query (LINQ): Simplifies querying data from different sources using a unified syntax.
  • Expressive Queries: Enables SQL-like queries for improved code readability.
  • Data Sources: Works with arrays, databases, XML, and more.
• Benefits
  • Enhanced Productivity: Reduces code and boosts developer efficiency.
  • Readability: Concise queries resemble natural language, aiding maintainability.
  • Type Safety: Strong typing reduces runtime errors.
• Components
  • LINQ to Objects: Manipulates in-memory data (e.g., arrays).
  • LINQ to SQL: Queries relational databases.
  • LINQ to XML: Manipulates XML data.
  • LINQ to Entities: Works with Entity Framework for data querying.
• Query Structure
  • Keywords: Utilizes from, where, select, and more.
  • Fluent Syntax: Supports method chaining.
  • Deferred Execution: Lazily evaluates queries.
• Query Operators
  • Standard Operators: Includes Where, Select, OrderBy, and more.
  • Custom Operators: Extend LINQ’s functionality.
• Examples
  • Filtering: Where to filter based on conditions.
  • Projection: Select for extracting specific data.
  • Sorting: OrderBy for data sorting.
  • Grouping: GroupBy to group based on attributes.
  • Joining: Join to combine data from sources.
• Performance
  • Optimization: Understand execution and optimization for better performance.
  • Materialization: Awareness of data retrieval impacts performance.
• Integration
  • Anonymous Types: Often used to structure query results.
  • Implicit Typing: var for type inference with LINQ.

Introduction to LINQ Queries

All LINQ query operations consist of three distinct actions:

1. Obtain the data source.

2. Create the query.

3. Execute the query.

LINQ Query Operations

LINQ (Language Integrated Query) is a feature in C# that enables data querying and manipulation within your code. LINQ supports query syntax and method syntax for defining queries.

1. Filtering

• Where: Filters elements based on a specified condition.
• OfType: Filters elements to include only those of a specified type.

2. Projection

• Select: Projects each element of a collection into a new form.
• SelectMany: Projects and flattens a collection of collections.

3. Ordering

• OrderBy: Orders elements in ascending order based on a specified key.
• OrderByDescending: Orders elements in descending order based on a specified key.

4. Grouping

• GroupBy: Groups elements by a specified key and creates groups of elements with the same key.

5. Aggregation

• Count: Counts the number of elements in a collection.
• Sum: Computes the sum of values in a collection.
• Average: Computes the average of values in a collection.

6. Joining

• Join: Joins two collections based on a common key.
• GroupJoin: Joins two collections and groups the results based on a common key.

7. Set Operations

• Union: Combines two collections, removing duplicates.
• Intersect: Finds elements common to both collections.
• Except: Finds elements in one collection not in another.

LINQ Query Operations provide a concise and readable way to perform complex data manipulations.

Things I want to know more about

I want to know more about when LINQ is used in bigger companies and how useful it is.

I want to learn more about using LINQ queries on my API call data.