Overview (restSQL)

Packages
Package	Description
org.restsql.core	Contains core framework interfaces, an API for deployments that use restSQL as a library, rather than an HTTP service.
org.restsql.core.sqlresource	Contains classes that model the SQL Resource definition XML document.
org.restsql.security	Contains classes that provide security, such as authorization.

restSQL is an ultra-lightweight data access layer for HTTP and Java clients. restSQL is a persistence framework or engine in the middle tier of a classic three tier architecture: client, application server and database. It may also be embedded in any middle-tier as a Java library.

What it is

an SQL generator with Java and HTTP APIs
uses a simple RESTful HTTP API with XML or JSON serialization
presents flat or hierarchical views of relational database tables
organizes access through query-able and updatable database views called SQL Resources
uses declarative authorization
offers declarative and plugin mechanisms for implementing domain constraints and business logic
a JEE web application or a Java library
platform, JEE container and database agnostic

What it is Not

an HTTP to JDBC/ODBC bridge that tunnels SQL over HTTP
an Object-Relational Mapping tool (ORM) that maps tables to objects
a database or a data storage engine
a sophisticated query or report generator
an OLAP-style cube or data warehousing engine

Where it could be Used

Applications needing:

basic CRUD (Create-Read-Update-Delete) access to relational databases
a database abstraction layer
a lighter-weight alternative to ORM (e.g. ADO or EJB)
a lighter-weight alternative to WSDL/SOAP

Motivation

For many apps:

Conventional ORM is too heavyweight
- We've gone overboard with objects
- Oodles of classes, interfaces, deployment descriptors
- OQL - another language to learn
Conventional ORM is inflexible
- A domain object layer rarely serves multiple apps well
- Entity objects can be joined into arbitrary views
- More accidental complexity: code required to join entities
Conventional Web Services is too heavyweight
- WSDL and SOAP are complicated
- RESTful Web Services and WADL are simpler

The bottom line – 80/20

restSQL is targeted at the 80% of data access that is basic CRUD
No more messing around with basic SQL, some complex ORM tool, oodles of Objects and Interfaces, or quirky OQL.
Developers can spend their efforts on the remaining 20% of the database access, using an approach appropriate to the problem.
restSQL frees developers to focus on the essential work of software engineering:
- architecture, data modeling, workflow, UI design, business logic, testing and tuning
- and making our stakeholders happy

Description

restSQL is a different kind of middle tier framework. There is no object-relational mapping, no object query language and no beans. It is intentionally not an object-oriented view of the database. It provides an interface based on Representational State Transfer (REST) principles, which use HTTP's built-in features, rather than abstracting away from them. The framework makes it simple to put a RESTful interface on a database.

The framework is used in two ways: 1) Clients may connect directly to the restSQL engine using the HTTP API, and 2) your Services use a Java API.

Optionally, applications provide Java-based triggers to manage data validation and business logic. restSQL right-sizes five technologies: SQL, XML, JSON, Java and HTTP. SQL is embedded in XML files that define resources, like database views, that may be queried, added to, updated or deleted using HTTP or a Java access API. Data is serialized over XML or JSON. The framework itself is written in Java and deployed as a JAR or WAR on a standard JEE Container.

restSQL enables you to build multiple SQL Resources, queryable and updatable database views that exist on the middle tier and are accessible via Java or HTTP APIs. SQL Resources may be flat views or hierarchical parent-child. The SQL Resource is defined in an XML file. The core of the definition is the query expression, an SQL DML expression.

restSQL – Trim your Middle