How do I Select a query in LINQ?

LINQ query syntax always ends with a Select or Group clause. The Select clause is used to shape the data. You can select the whole object as it is or only some properties of it. In the above example, we selected the each resulted string elements.

What represents entire XML document with all associated metadata in LINQ to XML?

The difference is that an XElement type represents an XML fragment while the XDocument type represents an entire XML document with all associated meta-data.

Which of the following can serve as a data source for a LINQ query in C#?

However, the basic rule is very simple: a LINQ data source is any object that supports the generic IEnumerable interface, or an interface that inherits from it. Types such as ArrayList that support the non-generic IEnumerable interface can also be used as a LINQ data source.

What is the difference between XDocument and XElement?

XDocument represents a whole XML document. It is normally composed of a number of elements. XElement represents an XML element (with attributes, children etc). It is part of a larger document.

What is select in LINQ C#?

The Select() method invokes the provided selector delegate on each element of the source IEnumerable sequence, and returns a new result IEnumerable sequence containing the output of each invocation.

What is the difference between select and where in LINQ?

Select will always return the same number of elements in the list (regardless of a filter condition you may have). Where can return less elements depending on your filter condition.

Does LINQ work with XML?

LINQ to XML is a LINQ-enabled, in-memory XML programming interface that enables you to work with XML from within the . NET programming languages. LINQ to XML is like the Document Object Model (DOM) in that it brings the XML document into memory.

What a LINQ query returns in LINQ to object?

Language-Integrated Query (LINQ) makes it easy to access database information and execute queries. By default, LINQ queries return a list of objects as an anonymous type. You can also specify that a query return a list of a specific type by using the Select clause.

Why we use LINQ instead of SQL?

SQL isn’t broken, so why fix it? Why do we need another querying language? The popular answer is that LINQ is INtegrated with C# (or VB), thereby eliminating the impedance mismatch between programming languages and databases, as well as providing a single querying interface for a multitude of data sources.

Should I use LINQ or Entity Framework?

If your database is straightforward and simple, LINQ to SQL will do. If you need logical/abstracted entities on top of your tables, then go for Entity Framework. Entity Framework allows for a layer of abstraction of top of the database.

What is the difference between XmlDocument and XDocument?

XDocument is from the LINQ to XML API, and XmlDocument is the standard DOM-style API for XML.

What’s the difference between XmlDocument and XmlReader?

XmlDocument is very easy to use. Its only real drawback is that it loads the whole XML document into memory to process. Its seductively simple to use. XmlReader is a stream based reader so will keep your process memory utilization generally flatter but is more difficult to use.

What is an XML database and how does it work?

XML databases store data XML formatted documents. The data can be retrieved via query, updated and edited, removed or returned to the database. Extensible Markup Language (XML) is readable by both humans and computers, making it, at times, more convenient than relational databases that may require extensive knowledge to interpret.

What is native XML database?

Native XML database is based on the container rather than table format. It can store large amount of XML document and data. Native XML database is queried by the XPath -expressions. Native XML database has an advantage over the XML-enabled database. It is highly capable to store, query and maintain the XML document than XML-enabled database.

How do I convert a database to an XML file?

Assuming your database is small enough that you can easily load it into memory. Create classes that model your database. Add DataContract attributes to them to indicate how you want them serialized. Use DataContractSerializer to serialize your database to XML and then save it to disk. Delete any old file called .old

What is the best free XML database?

Sedna is a free native XML database which provides a full range of core database services – persistent storage, ACID transactions, security, indices, hot backup. Flexible XML processing facilities include W3C XQuery implementation, tight integration of XQuery with full-text search facilities and a node-level update language.