# Editing DOCTYPE declarations

The DOCTYPE declaration in an XML file is used at the beginning of it to associate it with a DTD file. You can edit your DOCTYPE declaration to change the DTD file your XML file is associated with.

The following instructions were written for the Resource perspective, but they will also work in many other perspectives.

To edit your DOCTYPE declaration, complete the following steps:

1. In the Design view of the XML editor, right-click DOCTYPE and click Edit DOCTYPE.
2. The value in the Root element name field should match the root element of your XML file exactly. You should only edit the value in this field if your root element changes.
3. You can select a Public ID for any existing XML Catalog entries by clicking Browse. The value in the Public ID field is the Public Identifier. It is used to associate the XML file (using an XML Catalog entry) with a DTD file. For more information, see Adding entries to the XML Catalog.
4. The value in the System ID field is the DTD the XML file is associated with. Type the path of the DTD file (or browse for it) you want the XML file associated with in this field.
   Note: When the XML file is processed by the XML processor, it will first try to use the Public ID to locate the DTD, and if this fails, it will use the System ID to find it.
5. Click OK.

If you do not have a DOCTYPE declaration in your XML file, you can right-click in the Design view and click Add DTD Information to add one.
Related concepts
XML file associations with DTDs and XML schemas
Related tasks
Editing with DTD or XML schema constraints
Adding entries to the XML Catalog
Updating XML files with changes made to DTDs and schemas
Editing in the Design view