What is element ref in XSD?
What is element ref in XSD?
The ref value must be a QName. The ref can include a namespace prefix. Prohibited if the containing element is the schema element. If the ref attribute is present, complexType, simpleType, key, keyref, and unique elements and nillable, default, fixed, form, block, and type attributes cannot be present.
How do I make an element optional in XSD?
Using in an XSD The element in the root schema has to be optional. Add attribute minOccurs=”0″ on the element to make it optional.
What is minOccurs and maxOccurs in XSD?
The minOccurs attribute specifies the minimum number of times that the element can occur. It can have a value of 0 or any positive integer. The maxOccurs attribute specifies the maximum number of times that the element can occur.
What is a simple element?
A simple element is an XML element that can contain only text. It cannot contain any other elements or attributes. It can be one of the types included in the XML Schema definition (boolean, string, date, etc.), or it can be a custom type that you can define yourself.
How do you reference an XML schema?
A XML Schema can be referenced from an XML document by defining the schemaLocation and noNamespaceSchemaLocation attributes. The ‘schemaLocation’ attribute is used to reference XML Schema(s) that are defined in a target-namespace.
Which is maxOccurs means in XSD?
The maxOccurs attribute specifies the maximum number of times that the element can occur. It can have a value of any positive integer greater than or equal to the value of the minOccurs attribute.
What does the ref attribute on an element in an XSD do?
However, a ref attribute refers to an external entity by its “id”, not “name”. According to all XSD documentation I’ve seen, the “ref” applies to a “name”, as seen here: w3schools.com/schema/el_element.asp (ref – Optional.
Which is an example of XSD in XML?
Examples to Implement XSD in XML. XML file using Schema Definition. Example #1. College detail with root element followed by child elements. Here individual Schema file is created with the perschema.xsd that should be included as the namespace in the XML document. Code: pre.xml
How are namespaces used in the XSD standard?
Namespaces are a mechanism for breaking up your schemas. Up until now we have assumed that you only have a single schema file containing all your element definitions, but the XSD standard allows you to structure your XSD schemas by breaking them into multiple files. These child schemas can then be included into a parent schema.
Where does the ref attribute come from in XML?
Basically it references another element that is delared elsewhere, which may or may not be the same schema document. For instance, it could come from an externally referenced schema in a different namespace.