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Databases
Complete the following slides with text, images and worked examples.
Use the following resources for research.
RM Unify Resource
EBook Resource
What is a database? Why do we use databases and give examples of
how they improve efficiency.
A database is a usually structured, persistent store of data. Databases can
allow for computing power to speed up searching and organising
compared to previous methods of storing large amounts of data while
normally making use easier.
In Database terms, what is a record / tuple / field / attribute?
In databases, records are related items of data which can be put into
databases.
A tuple is what makes up a record and consists of an ordered set of data.
A field is the data that determines the attributes of a record.
The attributes are the various properties of a field.
In Database terms, what is a serial / sequential file?
In databases, serial and sequential files are in a specific order of storage.
This means that searching requires the files to be searched in their order.
The advantage of this is that depending on the sorting of the order (such
as alphabetical) items can be found within a section in reduced time due
to less unnecessary searching.
In Database terms, what is indexing?
Indexing is used to organise and identify data based on name or data keys
for more efficient searching within a database.
In Database terms, what is a transaction / transaction file?
Transactions in databases just refers to any exchange or action regarding
the files within it. This includes the moving or modifying of files for
example. The transaction file keeps a log of the various transactions for
review later on.
What is CRUD in terms of transaction processing, how do they relate to
SQL statements?
CRUD stands of Create, Read, Update and Delete. These are all
transactions used by SQL’s for database management.
What is a flat-file database?
A flat-file database is a term for a large, organised database usually
containing a great deal of data with no relations to other tables.
What is a primary / secondary / foreign key?
The primary key is used for data which has no duplicates and is
completely unique within its database.
Secondary keys are related to primary keys and their data can be used to
identify primary keys.
Foreign keys are items which have come from other databases and are
placed into another.
What is a DBMS (sometimes an RDBMS)? Give features and examples for
retail / commercial use.
A (Relational) Database Management System is a type of software which
is used to manage databases. It does this with various searching
algorithms and a system of transactions which can be utilised by the user
to modify and maintain databases. Microsoft Access and MySQL are
examples of DBMS’s. The commercial application of DBMS’s could include
the management of products in a supermarket with a way to modify
barcodes, product names or delete products from the system.
What is an Entity Relation Diagram? Give examples.
An Entity Relation Diagram is used to overview and explain a database by
pointing out features such as records and links and areas where for
example a one to many relationship occurs.
In terms of Databases, describe and contrast the Physical, Logical and
User View.
The physical view refers to the actual location of data such as which
storage devices they are physically contained within such as hard disk
drives. This differs from the logical view which is the computational way
the data is presented to the person(s) managing the server. The user view
is what the end result user sees.