# Implement Data Access
*This portion takes up 25-30% of the exam*

### Perform I/O operations
Read and write files and streams; read and write from the network by using classes in the System.Net namespace; implement asynchronous I/O operations

### Consume data
Retrieve data from a database; update data in a database; consume JSON and XML data; retrieve data by using web services

### Query and manipulate data and objects by using LINQ
Query data by using operators, including projection, join, group, take, skip, aggregate; create methodbased LINQ queries; query data by using query comprehension syntax; select data by using anonymous types; force execution of a query; read, filter, create, and modify data structures by using LINQ to XML

### Serialize and deserialize data
Serialize and deserialize data by using binary serialization, custom serialization, XML Serializer, JSON Serializer, and Data Contract Serializer

### Store data in and retrieve data from collections
Store and retrieve data by using dictionaries, arrays, lists, sets, and queues; choose a collection type; initialize a collection; add and remove items from a collection; use typed vs. non-typed collections; implement custom collections; implement collection interfaces

### Preparation resources
* [File system and the registry (C# programming guide)](http://msdn.microsoft.com/library/vstudio/2kzb96fk.aspx)

###### tags: `Microsoft` `Certification`