Regarding XML schema, Unable to find correct behaviour of XML document

Question

I am new to XML schema and I am try to understand how they work. I have written a simple schema.Below is my xml schema.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 
    <xs:element name="employees" type="comType"/>
    <xs:complexType name="comType">
        <xs:sequence>
            <xs:element ref="employee" maxOccurs="2"/>
        </xs:sequence>
    </xs:complexType>
    <xs:element name="employee">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="name" type="xs:string"/>
                <xs:element name="address" type="xs:string"/>
            </xs:sequence>
            <xs:attribute name="id" type="xs:integer" use="required"/>
        </xs:complexType>
    </xs:element>
</xs:schema>

However I am bit confused what XML will be valid for this schema.When I am validating both of the below XML using notpad++ both of the below XML are not giving an error as I am expecting that XML with root element of employees should the correct one.

<?xml version="1.0" encoding="UTF-8"?>
<employees>
    <employee id="1">
        <name>xxxx</name>
        <address>xxx</address>
    </employee>
    <employee id="2">
        <name>yyyyy</name>
    <address>yyy</address>
    </employee>
</employees>    

and second XML is

<?xml version="1.0" encoding="UTF-8"?>

<employee id="1">
    <name>Deepak</name>
    <address>909</address>
</employee>

ANd the schema is

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 
<xs:element name="employees" type="comType"/>   
<xs:complexType name="comType">
<xs:sequence>
<xs:element ref="employee" maxOccurs="2"/>
</xs:sequence>
</xs:complexType>

<xs:element name="employee">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string"/>
<xs:element name="address" type="xs:string"/>
</xs:sequence>
<xs:attribute name="id" type="xs:integer" use="required"/>
</xs:complexType>
</xs:element>
</xs:schema>

Need help...

Answer 1

Both Xml instances are correct, as in Xml Schema, any globally defined <element> can serve as a root element. This is also discussed in answers to this other question.

As you have defined both employees and employee with the <xsd:element> element on the root level of your schema (i.e. directly nested within the <xsd:schema> element), either of these can be used as a root for an Xml instance document of your schema.

To prevent employee from being eligible as a root element, you could either completely inline the definition of the employee element instead of using <xs:element ref="employee" maxOccurs="2"/>, or you could name the content of the employee element and define that complexType on the schema root level, so you get a re-usable complex type that you can then indicate as the type of the employee element.