Sav Zigzag is a mobile object-relational DBMS that represents a Java library (API interface) working on PC, PDA and mobile phones. This API interface forms new powerful Java/Zigzag language, more efficient than PL/SQL. Zigzag algebraic expressions enable to process tabular and XML data. Unlike XSLT, Zigzag is not data filter; it reads many of XML files in one database and then generates and prints new XML files. The some peculiarities of database: many-valued data, multi-level classification, class inheritance, dynamic structure, and automatic data integrity control. The Sav Zigzag, working under one JVM, provides synchronous connection many of users with many of local databases.