Information Technology Reference
In-Depth Information
that. allows. you. to. ask. questions. (queries). and. get. answers.
(reports).from.your.database.
For.instance,.you.could.put.in.a.query.that.asks.your.DVD.
database.for.every.Brad.Pitt.movie.you.bought.in.the.last.2.
years,.and.it.would.create.a.list.of.the.matching.records.
To.do.this,.the.database.programming.would.check.the.
Actors. table. and. look. for. matches. to. Brad. Pitt.. It. would.
then. compare. the. reference. number(s). from. those. records.
that.relate.to.the.main.table.list.of.DVDs..Then.it.would.go.
through.that.list.and.check.the.date.range.you.entered.against.
the. dates. of. the. entries. in. that. table.. Finally,. the. database.
front-end.application.would.present.a.report.to.you.of.all.the.
items.in.the.database.that.matched.your.query..Depending.
on.what.you.asked.it.to.show.you.in.your.query,.it.can.create.
a.report.with.all.of.the.details.or.just.a.few.of.them,.or.even.
just.a.single.item.such.as.the.name.of.the.DVD.
Databases.can.be.stored.on.desktops,.laptops,.or.serv-
ers,.depending.on.their.use.and.the.need.for.access..Your.
simple. DVD. database. would. probably. be. stored. locally.
on. your. home. computer. or. laptop.. However,. a. large. and.
complex.human.resources.database.for.a.global.organiza-
tion.would.need.to.be.stored.on.a.very.powerful.and.large.
capacity.server.
In.most.cases,.especially. with.enterprise-level.databases,.
they. will. be. backed. up. on. a. regular. basis,. and. sometimes,.
for.disaster.recovery.or.just.performance.reasons,.they.may.
also.be.“mirrored.”.Mirroring.creates.an.exact.image.of.the.
database.either.on.a.separate.hard.drive,.a.separate.part.of.a.
large.hard.drive.or.set.of.drives,.or.even.in.a.physically.sepa-
rate.location.
This. is. important. to. understand. and. be. aware. of. if. you.
need.to.manage,.preserve,.or.analyze.data.from.a.database..
Any.or.all.of.these.physical.and.logical.locations.might.need.
to.be.searched.or.preserved.
On.the.enterprise.scale.there.are.a.number.of.more.com-
plex.and.expensive.database.applications.that.are.common..
