Enabling auto reconnect in mysql hibernate spring

in your spring config file append the url entry with the below sample   <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="${database.driverClassName}" /> <property name="url" value="${database.url}?characterEncoding=UTF-8&amp;autoReconnect=true"/> <property name="username" value="${database.user}" /> <property name="password" value="${database.password}" /> </bean>

HSQL File Connection

jdbc address : jdbc:hsqldb:file:///c:/hybris/data/hsqldb/mydb lib and jar location inside the zip – official source of HSQL db: http://sourceforge.net/projects/hsqldb/files/   HSQL Editor free : http://www.sql-workbench.net/downloads.html

Relational Algebra

Relational algebra, first described by E.F. Codd while at IBM, is a family of algebra with a well-founded semantics used for modelling the data stored in relational databases, and defining queries on it. To organize the data, first the redundant data and repeating groups of data are removed, which we call normalized. By doing this


The relational algebra consists of: a set of eight operators (which ones?) and a relational assignment operation The relational assignment operation allows us to assign a name to the result of a relational expression, for example if we take the product of two relations A and B, then: C ← A X B shows that