All posts tagged with 'JDBC'

How to retrieve tables of custom object types with JDBC


The following is not only a personal reminder for me but also a first try to answer some questions on Stack Overflow… You can create custom object types in an Oracle database like so: CREATE TYPE t_demo_object AS OBJECT ( some_number NUMBER, some_string varchar2(32) ) / Those types can have member functions, custom constructors and […]

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Oracle, JBDC, CallableStatements and named parameters


Update: Please take a note of comment #5 by DSurber. He works for Oracle and sheds some light on named parameters. In short: The names of the parameter do not refer to named placeholders in statement (like in JPA for example) but to PL/SQL named parameters!. Thank you very much. You might have wondered what […]

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Fixing hibernate “Cannot release connection” exception using DBCP and MySQL.


Every 8 hours i got a Hibernate exception “Cannot release connection” within a Java application using Hibernate, Apache DBCP on Tomcat: org.hibernate.exception.GenericJDBCException: Cannot release connection at org.hibernate.exception.SQLStateConverter.handledNonSpecificException( at org.hibernate.exception.SQLStateConverter.convert( at org.hibernate.exception.JDBCExceptionHelper.convert( at org.hibernate.exception.JDBCExceptionHelper.convert( .. .. Caused by: java.sql.SQLException: Already closed. Not only that the messages polluted my inbox, the exception was visible to the enduser, […]

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JDBC: Get autogenerated keys on a Oracle DB


With the current and latest Oracle JDBC Drivers it’s possible to retrieve one automatically generated key based on a sequence or any other arbitrary value (autogenerated-keys or identity columns in other databases). Certainly it isn’t as simple as just use using Statement.html#getGeneratedKeys() as it simply returns an emtpy resultset. After browsing around, i saw that […]

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