pooling the JDBC connection

2 Message(s) by 2 Author(s) originally posted in java beans

From: timasmith

Date: Monday, May 22, 2006

Hi,

I've entity beans which act purely in a stateless

A stateless {server} is one which treats each request as an
	independent transaction, unrelated to any previous request.
	This simplifies the server design because it does not need to
	allocate storage to deal with conversations in progress or
	worry about freeing it if a client dies in mid-transaction.  A
	disadvantage is that it may be necessary to include more
	information in each request and this extra information will
	need to be interpreted by the server each time.

	An example of a stateless server is a {World-Wide Web} server.
	These take in requests ({URLs}) which completely specify the
	required document and do not require any context or memory of
	previous requests.

	Contrast this with a traditional {FTP} server which conducts
	an interactive session with the user.  A request to the server
	for a file can assume that the user has been authenticated and
	that the current directory and transfer mode have been set.

service

<networking, programming> Work performed (or offered) by a
	{server}.  This may mean simply serving simple requests for
	data to be sent or stored (as with {file servers}, {gopher} or
	{http} servers, {e-mail} servers, {finger} servers, {SQL}
	servers, etc.); or it may be more complex work, such as that
	of {irc} servers, print servers, {X Windows} servers, or
	process servers.

	E.g. "Access to the finger {service} is restricted to the
	local {subnet}, for security reasons".

	(1997-09-11)

fashion -
essentially executing SQL

<language, database, standard> /S Q L/ An industry-standard
	language for creating, updating and, querying {relational
	database management systems}.

	SQL was developed by {IBM} in the 1970s for use in {System R}.
	It is the {de facto standard} as well as being an {ISO} and
	{ANSI} {standard}.  It is often embedded in general purpose
	programming languages.

	The first SQL standard, in 1986, provided basic language
	constructs for defining and manipulating {tables} of data; a
	revision in 1989 added language extensions for {referential
	integrity} and generalised {integrity} {constraints}.  Another
	revision in 1992 provided facilities for {schema} manipulation
	and {data administration}, as well as substantial enhancements
	for data definition and data manipulation.

	Development is currently underway to enhance SQL into a
	computationally complete language for the definition and
	management of {persistent}, complex objects.  This includes:
	generalisation and specialisation hierarchies, {multiple
	inheritance}, user defined {data types}, {triggers} and
	{assertions}, support for {knowledge based systems},
	{recursive query expressions}, and additional data
	administration tools.  It also includes the specification of
	{abstract data types} (ADTs), object identifiers, {methods},
	{inheritance}, {polymorphism}, {encapsulation}, and all of the
	other facilities normally associated with object data
	management.

	The emerging {SQL3} standard is expected to be complete in
	1998.

	According to Allen G. Taylor, SQL does _not_ stand for
	"Structured Query Language".  That, like "SEQUEL" (and its
	pronunciation /see'kw*l/), was just another unofficial name
	for a precursor of SQL.  However, the IBM SQL Reference manual
	for DB2 and Craig Mullins's "DB2 Developer's Guide" say SQL
	_does_ stand for "Structured Query Language".

	{SQL Standards (http://www.jcc.com/sql_stnd.html)}.

	{An SQL parser
	(ftp://ftp.ora.com/published/oreilly/nutshell/lexyacc/)} is
	described in "Lex & Yacc", by Levine, Mason & Brown published
	by O'Reilly.

	{The 1995 SQL Reunion: People, Projects, and Politics
	(http://www.mcjones.org/System_R/SQL_Reunion_95/)}.

	["A Guide to the SQL Standard", C.J. Date, A-W 1987].

	["SQL for Dummies", Allen G. Taylor, IDG Books Worldwide].

	(2005-11-17)

and performing business logic

1. <philosophy, mathematics> A branch of philosophy and
	mathematics that deals with the formal principles, methods and
	criteria of validity of {inference}, reasoning and
	{knowledge}.

	Logic is concerned with what is true and how we can know
	whether something is true.  This involves the formalisation of
	logical arguments and {proofs} in terms of symbols
	representing {propositions} and {logical connectives}.  The
	meanings of these logical connectives are expressed by a set
	of rules which are assumed to be self-evident.

	{Boolean algebra} deals with the basic operations of truth
	values: AND, OR, NOT and combinations thereof.  {Predicate
	logic} extends this with existential and universal
	{quantifiers} and symbols standing for {predicates} which may
	depend on variables.  The rules of {natural deduction}
	describe how we may proceed from valid premises to valid
	conclusions, where the premises and conclusions are
	expressions in {predicate logic}.

	Symbolic logic uses a {meta-language} concerned with truth,
	which may or may not have a corresponding expression in the
	world of objects called existance.  In symbolic logic,
	arguments and {proofs} are made in terms of symbols
	representing {propositions} and {logical connectives}.  The
	meanings of these begin with a set of rules or {primitives}
	which are assumed to be self-evident.  Fortunately, even from
	vague primitives, functions can be defined with precise
	meaning.

	{Boolean logic} deals with the basic operations of {truth
	values}: AND, OR, NOT and combinations thereof.  {Predicate
	logic} extends this with {existential quantifiers} and
	{universal quantifiers} which introduce {bound variables}
	ranging over {finite} sets; the {predicate} itself takes on
	only the values true and false.  Deduction describes how we
	may proceed from valid {premises} to valid conclusions, where
	these are expressions in {predicate logic}.

	Carnap used the phrase "rational reconstruction" to describe
	the logical analysis of thought.  Thus logic is less concerned
	with how thought does proceed, which is considered the realm
	of psychology, and more with how it should proceed to discover
	truth.  It is the touchstone of the results of thinking, but
	neither its regulator nor a motive for its practice.

	See also fuzzy logic, logic programming, arithmetic and logic unit,
	first-order logic,

	See also {Boolean logic}, {fuzzy logic}, {logic programming},
	{first-order logic}, {logic bomb}, {combinatory logic},
	{higher-order logic}, {intuitionistic logic}, {equational
	logic}, {modal logic}, {linear logic}, {paradox}.

	2. <electronics> {Boolean} logic circuits.

	See also {arithmetic and logic unit}, {asynchronous logic},
	{TTL}.

	(1995-03-17)

and then
returning business objects.

I establish the JDBC

<database, programming> (JDBC) Part of the {Java Development
	Kit} which defines an {application programming interface} for
	{Java} for standard {SQL} access to {databases} from Java
	{programs}.

	{Home
	(http://java.sun.com/products/jdk/1.1/docs/guide/jdbc/index.html)}.

	{FAQ (http://www.yoyoweb.com/Javanese/JDBC/FAQ.html)}.

	See also {Open Database Connectivity}.

	(1997-09-04)

connection manually and all the beans *seem* to be
using the same connection since it is accessed statically. I dont know
whether that creates a problem if the beans are all their own threads..
anyway.

I am all for some pooling - I vaguely remember someone suggesting that
standalone JDBC can easily pool for you - without a container or
anything else.

If so I am not sure what I'd get from an EJB

<specification, business, programming> (EJB) A {server}-side
	{component architecture} for writing reusable {business logic}
	and {portable} {enterprise} applications.  EJB is the basis of
	{Sun}'s {Java 2 Platform, Enterprise Edition} (J2EE).

	Enterprise JavaBean components are written entirely in {Java}
	and run on any EJB compliant server.  They are {operating
	system}, {platform}, and {middleware} independent, preventing
	vendor {lock-in}.

	EJB servers provide system-level services (the "plumbing")
	such as {transactions}, security, {threading}, and
	{persistence}.

	The EJB architecture is inherently transactional,
	{distributed}, {multi-tier}, {scalable}, secure, and {wire
	protocol} neutral - any {protocol} can be used: {IIOP},
	{JRMP}, {HTTP}, {DCOM} etc.  EJB 1.1 requires {RMI} for
	communication with components.  EJB 2.0 is expected to require
	support for RMI/IIOP.

	EJB applications can serve assorted clients: {browsers}, Java,
	{ActiveX}, {CORBA} etc.  EJB can be used to wrap {legacy
	systems}.

	EJB 1.1 was released in December 1999.  EJB 2.0 is in
	development.

	Sun claims broad industry adoption.  30 vendors are shipping
	server products implementing EJB.  Supporting vendors include
	{IBM}, {Fujitsu}, {Sybase}, {Borland}, {Oracle}, and
	{Symantec}.

	An alternative is Microsoft's MTS ({Microsoft Transaction
	Server}).

	{Home (http://java.sun.com/products/ejb/)}.

	{FAQ (http://java.sun.com/products/ejb/faq.html)}.

	(2000-04-20)

datasource beyond some
transaction management

1. Corporate power elites distinguished primarily by their
	distance from actual productive work and their chronic failure
	to manage (see also {suit}).  Spoken derisively, as in
	"*Management* decided that ...".

	2. Mythically, a vast bureaucracy responsible for all the
	world's minor irritations.  Hackers' satirical public notices
	are often signed "The Mgt"; this derives from the
	"Illuminatus!" novels.

	[{Jargon File}]

	(1995-02-28)

possibilities down

1. Not operating.  "The up escalator is down" is considered a
	humorous thing to say, and "The elevator is down" always
	means "The elevator isn't working" and never refers to what
	floor the elevator is on.  With respect to computers, this
	term has passed into the mainstream; the extension to other
	kinds of machine is still hackish.

	2. "go down" To stop functioning; usually said of the
	{system}.  The message from the {console} that every hacker
	hates to hear from the operator is "System going down in 5
	minutes".

	3. "take down", "bring down" To deactivate purposely, usually
	for repair work or {PM}.  "I'm taking the system down to work
	on that bug in the tape drive."  Occasionally one hears the
	word "down" by itself used as a verb in this sense.

	See {crash}; opposite: {up}.

	[{Jargon File}]

	(1994-12-07)

the road if I cant architect
around it.

So my question is a) can I pool with POJO and b) is it far better to
have the container do it?

Note I generate

To produce something according to an {algorithm} or program or
	set of rules, or as a (possibly unintended) {side effect} of
	the execution of an algorithm or program.

	The opposite of {parse}.

	[{Jargon File}]

	(1995-06-15)

and execute

<operating system, programming> The process of carrying out
	the {instructions} in a computer program by a computer.

	See also {dry run}.

	(1996-05-13)

my own SQL - no real

1. Not simulated.  Often used as a specific antonym to
	{virtual} in any of its jargon senses.

	2. <mathematics> {real number}.

	[{Jargon File}]

	(1997-03-12)

entity beans here.

thanks

Tim

From: Marc E

Date: Monday, May 22, 2006

I can tell you that pooling with POJO is pretty easy. I have been using c3p0
pool for over a year now with much success. No need for jndi or
anything...just straight up driver/url stuff that you pass when you
configure the pool and it handles the rest.

Hi,
I've entity beans which act purely in a stateless service fashion -
essentially executing SQL and performing business logic and then
returning business objects.
I establish the JDBC connection manually and all the beans *seem* to be
using the same connection since it is accessed statically. I dont know
whether that creates a problem if the beans are all their own threads..
anyway.
I am all for some pooling - I vaguely remember someone suggesting that
standalone JDBC can easily pool for you - without a container or
anything else.
If so I am not sure what I'd get from an EJB datasource beyond some
transaction management possibilities down the road if I cant architect
around it.
So my question is a) can I pool with POJO and b) is it far better to
have the container do it?
Note I generate and execute my own SQL - no real entity beans here.
thanks
Tim

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