Features Summary

General

• Original code, based on in-depth study of database theory and the SQL Standard
• Ahead of other open-source solutions in supported SQL features
• The fastest overall open-source SQL implementation for small and medium sized databases
• Three transaction control models, including lock based and MVCC models
• Fully multithreaded
• Compact code footprint

JAVA

• 100% Java
• Support JDK 1.1.x, 1.2.x, 1.3.x, 1.4.x, 1.5.x, 1.6.x in HyperSQL 1.8.1 and 1.5.x and 1.6.x in HyperSQL 2.0
• Extensive JDBC interface support with batch statement and scrollable ResultSet functionality
• Updatable, insertable ResultSet functionality
• Full JDBC DatabaseMetaData and ResultSetMetaData support
• Java stored procedures and functions
• Full support for PreparedStatement objects to speed up query processing

SQL

• Relational Database Management System, which can store Serializable Java objects
• Very extensive support for SQL:2008 Standard syntax, including most optional features
• Supports all base data types of the SQL Standard, including BINARY, BIT, BOOLEAN, date-time, INTERVAL, BLOB, CLOB
• Supports datetime and interval arithmetic with and without time zone
• Supports user-defined DOMAIN types, including type constraints
• Fast SELECT, INSERT, DELETE, UPDATE and MERGE operations
• INNER, LEFT OUTER, RIGHT OUTER and FULL joins
• NATURAL, USING and UNION joins
• UNION, EXCEPT, INTERSECT, including use of parentheses, limits and offsets, ALL, DISTINCT and CORRESPONDING keywords
• Scalar (single value) SELECTS, row, table and correlated subqueries including IN, EXISTS, ANY, ALL
• Views, temporary tables and sequences
• Updatable views
• Primary key, unique and check constraints on single or multiple columns 
• Referential Integrity (foreign keys) on multiple columns with full cascading options (delete, update, set null, set default)
• ORDER BY, GROUP BY, HAVING, FETCH (LIMIT) and OFFSET 
• COUNT, SUM, MIN, MAX, AVG and statistical aggregate functions
• Full support for SQL expressions such as CASE .. WHEN .. ELSE .. , NULLIF , BETWEEN, MATCHES, etc.
• SQL standard autoincrement IDENTITY column support plus sequences
• SQL standard GENERATED columns calculated using other columns and function calls
• Very extensive set of built-in functions
• Transaction COMMIT, ROLLBACK and SAVEPOINT support
• Multiple schemata per database
• Triggers, implemented as Java classes, or as SQL statements
• Database security with passwords, user rights and roles with GRANT and REVOKE down to column level
• Extensive set of ALTER TABLE commands, including change of table column type
• SQL stored procedures and functions
• INSTEAD OF triggers which enable insert, update and delete on several table with a single statement
• Full set of SQL Standard INFORMATION SCHEMA views
• Query optimizer can use indexes for AND, OR, IN predicates

Persistence

• In-memory tables for fastest operation
• Disk based tables for large data sets
• Text tables with external file data sources such as CSV files can be used as SQL tables
• CLOB and BLOB storage up to 64 TB with no memory limit on individual LOB size
• Disk tables (CACHED TABLE) up to 256GB and text tables up to 2GB each
• Size of each string or binary item only limited by memory
• Fast startup and shutdown with internal incremental backup feature
• Online and offline backup capability
• Database dump as SQL script with or without data

Deployment

• Embedded (into Java applications) and Client-Server operating modes
• Three client server protocols: HSQL, HTTP and HSQL-BER - can run as an HTTP web server - all with SSL option
• Can be used in applets, read-only media (CD), inside jars, webstart and embedded applications
• Multiple databases per JVM
• ODBC support

Utilities

• Powerful and compact Java command line and GUI tools for database management
• Transfer tool for conversion of databases to / from other popular database management systems