LINQ Overview 1

LINQ is short for Language Integrated Query, which is integrated in. net.Programming Language. Has become an integral part of the programming language.ProgramThe compilation syntax check, rich metadata, smart sensing, static type, and other advantages can be obtained. In addition, it also enables queries to conveniently Query Information in the memory, not just external data sources.

LINQ defines a set of standard query operators for all. in the programming language of the. NET platform, you can directly declare a unified method for cross-, filtering, and projection operations. The standard query operator allows the query to act on all sources based on ienumerable <t> interfaces, it also allows third-party specific domain operators suitable for the target domain or technology to expand the standard query operator set. More importantly, third-party operators can use their own implementation of additional services to freely replace standard query operators. According to the Convention of the LINQ mode, these queries prefer the same language integration and tool support as standard query operators.

Let's take a look at the overall LINQ architecture.

In. net3.5, Microsoft provides us with some namespaces.

There are five parts of LINQ to objects, LINQ to datasets, LINQ to SQL, LINQ to entities, and LINQ to XML.

A. Net Language Integrated Query Based on relational data. It is used to manage relational data in the form of objects and provides rich query functions. It is built on the integration of SQL-Based Schema definitions in public language systems. When maintaining the relational model expression capability and the performance of direct query and Evaluation of underlying storage, this integration provides strong types of relational data.

In the system. xml. LINQ namespace, implement the XML operations. Uses efficient, easy-to-use, in-memory XML tools to provide XPath/XQuery functions in the host programming language.