An XML schema is a description of a type of XML document, typically expressed in terms of constraints on the structure and content of documents of that type, above and beyond the basic syntactical constraints imposed by XML itself.
The XML Schema language is also referred to as XML Schema Definition (XSD).
The purpose of an XML Schema is to define the legal building blocks of an XML document:
- the elements and attributes that can appear in a document
- the number of (and order of) child elements
- data types for elements and attributes
- default and fixed values for elements and attributes
In the XML world, hundreds of standardized XML formats are in daily use.
Many of these XML standards are defined by XML Schemas.
XML Schema is an XML-based (and more powerful) alternative to DTD.
One of the greatest strength of XML Schemas is the support for data types.
- It is easier to describe allowable document content
- It is easier to validate the correctness of data
- It is easier to define data facets (restrictions on data)
- It is easier to define data patterns (data formats)
- It is easier to convert data between different data types
Curriculum
- 16 Sections
- 45 Lessons
- 10 Weeks
Expand all sectionsCollapse all sections
- XML Schema IntroductionAn XML Schema describes the structure of an XML document. The XML Schema language is also referred to as XML Schema Definition (XSD).7
- XSD How To?XML documents can have a reference to a DTD or to an XML Schema.4
- XSD - The ElementThe element is the root element of every XML Schema.2
- XSD Simple ElementsXML Schemas define the elements of your XML files. A simple element is an XML element that contains only text. It cannot contain any other elements or attributes.3
- XSD AttributesAll attributes are declared as simple types.5
- XSD Restrictions/FacetsRestrictions are used to define acceptable values for XML elements or attributes. Restrictions on XML elements are called facets.7
- XSD Complex ElementsA complex element contains other elements and/or attributes.2
- XSD Empty ElementsAn empty complex element cannot have contents, only attributes.1
- XSD Elements OnlyAn "elements-only" complex type contains an element that contains only other elements.1
- XSD Text-Only ElementsA complex text-only element can contain text and attributes.1
- XSD Mixed ContentA mixed complex type element can contain attributes, elements, and text.1
- XSD IndicatorsWe can control HOW elements are to be used in documents with indicators.3
- XSD The ElementThe element enables us to extend the XML document with elements not specified by the schema!1
- XSD The ElementThe element enables us to extend the XML document with attributes not specified by the schema!1
- XSD Element SubstitutionWith XML Schemas, one element can substitute another element.2
- An XSD ExampleThis chapter will demonstrate how to write an XML Schema. You will also learn that a schema can be written in different ways.4
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FAQs
The purpose of a schema is to define and describe a class of XML documents by using these constructs to constrain and document the meaning, usage and relationships of their constituent parts: datatypes, elements and their content, attributes and their values, entities and their contents and notations
To create an XML schema
Open an XML file in Visual Studio.
On the menu bar, choose XML > Create Schema. An XML Schema document is created and opened for each namespace found in the XML file. Each schema is opened as a temporary miscellaneous file. The schemas can be saved to disk, added to your project, or discarded.
Validation is the most common use for schemas in the XML world.
Advantages of Using Schema
A SQL schema can be easily transferred to another user.
A schema may be shared by several users.
It enables you to transfer database objects between schemas.
We gain greater power over the access and protection of database objects.
XML schema is a language which is used for expressing constraint about XML documents. There are so many schema languages which are used now a days for example Relax- NG and XSD (XML schema definition). An XML schema is used to define the structure of an XML document
XML defines the syntax of elements and attributes for structuring data in a well-formed document. XSD (aka XML Schema Definition), like DTD before, powers the eXtensibility in XML by enabling the user to define the vocabulary and grammar of the elements and attributes in a valid XML document. Save this answer.
An XML schema is a document that defines the valid content of XML files. An XML schema file, like a DTD file, contains only metadata. An XML schema defines the structure and type of elements and attributes for an associated XML file
An XML Schema is a language for expressing constraints about XML documents. There are several different schema languages in widespread use, but the main ones are Document Type Definitions (DTDs), Relax-NG, Schematron and W3C XSD (XML Schema Definitions).
After you import an XML schema collection by using CREATE XML SCHEMA COLLECTION, the schema components are stored in the metadata.
Extensible Markup Language (XML) lets you define and store data in a shareable manner. XML supports information exchange between computer systems such as websites, databases, and third-party applications.
