The Digital archive database tool (DADT) is a tool for making sophisticated database application systems on the Web. As a major part of digital archives, metadata is so complicated that DADT might be very helpful to handle it. DADT is somewhat a middleware associated with a RDBMS. Right now, only MySql and Oracle are bound, but it is easy to extend the list. The DBMS is kept transparent as much as possible. DADT may take care of tiny differences, and generate different SQL statements for various DBMS, if necessary. Sometimes you almost change nothing in your application for changing a DBMS.
DADT is a highly schema-driven tool. As long as the database schema is decided, you may follow some simple rules to design Web pages according to the schema, and obtain the support of DADT. Four kinds of Web pages are supported. A management page is used to insert, update, delete and search a set of related tables that form a hierarchy. It contains some forms, one form for one table. Types of input elements are freely chosen. Tens of tables can be handled at the same time. Severe entry checks may be set. Since the structures of most metadata standards are hierarchical, if you choose to decompose them into tables, DADT might help a lot. A query page is purely for end-users to search. A list page shows partial search results line by line as a directory. You can make a list page very quickly and enjoy the convenience of sort. A report page shows details of search results to end-users. Since the layouts of reports could be quite different, this is the only kind of pages you have to program with PHP.
DADT also provides some XML utilities for exchange of metadata. The schema binder connects XML schema and database schema. The XML importer imports XML documents into relational databases by way of the schema binder. The XML exporter does the reverse.