uk.ac.ic.doc.automed.util.db
Class DBPostgres

java.lang.Object
  uk.ac.ic.doc.automed.util.db.DBAccess
      uk.ac.ic.doc.automed.util.db.DBPostgres

public class DBPostgres
extends DBAccess

Field Summary

Fields inherited from class uk.ac.ic.doc.automed.util.db.DBAccess

connections, dbFQPath, password, props, user

Method Summary

void	commit() Only use this method if you want to commit changes immediately. In HSQLDB this can be avoided by using "SET _writeDelay 0 MILLIS" in dbname.script file.
protected void	executeCommand(java.lang.String cmd) Mostly used for executing control commands, e.g.
java.sql.ResultSet	executeQuery(java.lang.String expression) This method is used for SELECT statement
void	executeStatement(java.lang.String expression) This method is used for making changes to data, e.g.
java.sql.Connection	getConnection()
static DBPostgres	getDBInstance(java.lang.String dbFQPath, java.lang.String user, java.lang.String password, java.util.Properties props) Create a new DB process instance for a data source named dsName. As such, we can initiate multiple databases (data sources) at the same time.
boolean	isTableExist(java.lang.String name) Return a result set of table names for manipulation
java.sql.Connection	newConnection() Creates a new connection to add to the pool
void	printResultSet(java.sql.ResultSet rs) A test method to print in simple tabular form a result set
void	setAutoCommit(boolean autoCommit) Different data sources understands auto-commit differently.

Methods inherited from class uk.ac.ic.doc.automed.util.db.DBAccess

closeConnection, getCurrentRow, shutdown

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getDBInstance

public static DBPostgres getDBInstance(java.lang.String dbFQPath,
                                       java.lang.String user,
                                       java.lang.String password,
                                       java.util.Properties props)
                                throws DBInstanceException

Create a new DB process instance for a data source named dsName.
As such, we can initiate multiple databases (data sources) at the same time.

Parameters:

dbFQPath - the fully qualified path to data source

user - user to connect to

password - password associated to user

props - a Properties object specifying extra properties
E.g. HSQLDB may requires write_delay = 0 for auto-commit

Throws:

DBInstanceException

newConnection

public java.sql.Connection newConnection()
                                  throws java.sql.SQLException

Description copied from class: DBAccess

Creates a new connection to add to the pool

Overrides:

newConnection in class DBAccess

Throws:

java.sql.SQLException

getConnection

public java.sql.Connection getConnection()

Specified by:

getConnection in class DBAccess

setAutoCommit

public void setAutoCommit(boolean autoCommit)
                   throws java.sql.SQLException

Different data sources understands auto-commit differently. This method
tries to encapsulate the operation to set auto-commit

Specified by:

setAutoCommit in class DBAccess

Parameters:

autoCommit - a boolean value: true = auto-commit; false otherwise

Throws:

java.sql.SQLException

commit

public void commit()
            throws java.sql.SQLException

Only use this method if you want to commit changes immediately.
In HSQLDB this can be avoided by using "SET _writeDelay 0 MILLIS" in dbname.script
file.

Specified by:

commit in class DBAccess

Throws:

java.sql.SQLException

executeQuery

public java.sql.ResultSet executeQuery(java.lang.String expression)
                                throws java.sql.SQLException

This method is used for SELECT statement

Specified by:

executeQuery in class DBAccess

Parameters:

expression - is an SQL statement to use

Returns:

ResultSet object of the result data

Throws:

java.sql.SQLException

executeStatement

public void executeStatement(java.lang.String expression)
                      throws java.sql.SQLException

This method is used for making changes to data, e.g. INSERT, DELETE, UPDATE

Specified by:

executeStatement in class DBAccess

Parameters:

expression - is an SQL statement to use

Throws:

java.sql.SQLException

executeCommand

protected void executeCommand(java.lang.String cmd)
                       throws java.sql.SQLException

Mostly used for executing control commands, e.g. SHUTDOWN, SET ...

Overrides:

executeCommand in class DBAccess

Parameters:

cmd - the command to execute

Throws:

java.sql.SQLException

isTableExist

public boolean isTableExist(java.lang.String name)
                     throws java.sql.SQLException

Return a result set of table names for manipulation

Overrides:

isTableExist in class DBAccess

Throws:

java.sql.SQLException

printResultSet

public void printResultSet(java.sql.ResultSet rs)
                    throws java.sql.SQLException

A test method to print in simple tabular form a result set

Overrides:

printResultSet in class DBAccess

Throws:

java.sql.SQLException