Senior Staff Engineer, Sun Microsystems Saur Saucer Separation Rick Hillegas Senior Staff Engineer, Sun Microsystems

Derby-style table functions to be introduced in Derby 10.4 Use SQL on non-relational data Tear-off subsets of other databases

Overview of Table Functions Log Files XML Reports External DBMSes Snapshots

O Overview of Table Functions Implementing a Table Function Demo Code Creating a Table Function Invoking a Table Function Optimizing a Table Function O

Implementing a Table Function Implement java.sql.ResultSet – extend a demo class if appropriate Stub out all methods except: next() close() getXXX() -- for the datatypes of your columns Create a public static method which returns your implementation of java.sql.ResultSet

Demo code in java/demo/vtis... Table Function for rows of String columns Table Function wrapping a text file Table Function wrapping a properties file Table Function wrapping an xml file Table Function wrapping external query Subscription to foreign SQL data

Creating a Table Function

Invoking a Table Function

Optimizing a Table Function Advanced topic Class containing Table Function must have a 0-arg constructor It must implement org.apache.derby.vti.VTICosting

Log Files Plain text log files XML log files

Plain text log files Have regular structure Sequence of records (rows) Each record has fields (columns) SQL is a great tool for mining these records

XML Log Files Again, regular structure Repeating elements (rows) With attributes/sub-elements (columns) SQL is a great tool for mining these files

Reports Exported in XML Easy to mine using SQL and Table Functions

External DBMSes Foreign DBMS Data Migrating Foreign Data into Derby

Foreign DBMS data Use Table Functions to import data from foreign databases Demo classes make it easy to create a Table Function which runs a query against a foreign database

Migrate foreign data into Derby Use Demo classes to create Table Function which runs a foreign query Use 'create table ... as select' to create Derby table from Table Function shape Use 'insert into ... select * from' to pipe data from foreign database into Derby

Snapshots Use Demo classes to declare a parameterized subscription to foreign data Use Demo procedures to plug in new parameters and tear-off a fresh copy of the subscription