METS: Metadata Encoding and Transmission Standard.METS is intended to provide a standardized XML format for transmission of complex digital library objects between systems. As such, it can be seen as filling a role similar to that defined for the Submission Information Package (SIP), Archival Information Package (AIP) and Dissemination Information Package (DIP) in the Reference Model for an Open Archival Information System. The root element <mets> establishes the container for the information being stored and/or transmitted by the standard.
ID (ID/O): This attribute uniquely identifies the element within the METS document, and would allow the element to be referenced unambiguously from another element or document via an IDREF or an XPTR. For more information on using ID attributes for internal and external linking see Chapter 4 of the METS Primer.
OBJID (string/O): Is the primary identifier assigned to the METS object as a whole. Although this attribute is not required, it is strongly recommended. This identifier is used to tag the entire METS object to external systems, in contrast with the ID identifier.
PROFILE (string/O): Indicates to which of the registered profile(s) the METS document conforms. For additional information about PROFILES see Chapter 5 of the METS Primer.
TYPE (string/O): Specifies the class or type of the object, e.g.: book, journal, stereograph, dataset, video, etc.
Wildcard: ANY attribute from ANY namespace OTHER than 'http://www.loc.gov/METS/'
Source
<xsd:element name="mets"><xsd:annotation><xsd:documentation xml:lang="en">METS: Metadata Encoding and Transmission Standard. METS is intended to provide a standardized XML format for transmission of complex digital library objects between systems. As such, it can be seen as filling a role similar to that defined for the Submission Information Package (SIP), Archival Information Package (AIP) and Dissemination Information Package (DIP) in the Reference Model for an Open Archival Information System. The root element <mets> establishes the container for the information being stored and/or transmitted by the standard.</xsd:documentation></xsd:annotation><xsd:complexType><xsd:complexContent><xsd:extension base="metsType"/></xsd:complexContent></xsd:complexType></xsd:element>