CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
1.
differentiate among terms
used
in
Information
Management;
For example, fields, records, tables, files, database
and database management system.
What is Information Management?
Information Management (IM) is the collection and management of information from one or more
sources and the distribution of that information to one or more audiences. This sometimes involves those
who have a stake in, or a right to that information. Management means the organization of and control
over the structure, processing and delivery of information. In short, Information Management entails
organizing, retrieving, acquiring and maintaining information.
http://en.wikipedia.org/wiki/Information_management
Information Management helps you deliver data that is integrated, accurate, and timely across the
enterprise. With Information Management, you can provide trusted data for initiatives like business
transaction processing, business intelligence, data warehousing, data migration, or master data
management.
http://www.businessobjects.com/product/im/
Definitions of Information Management on the Web:





Information Management is the means by which an organisation maximises the efficiency with
which it plans, collects, organises, uses, controls, stores, disseminates, and disposes of its
Information, and through which it ensures that the value of that information is identified and
exploited to the maximum extent possible. The aim has often been described as getting the right
information to the right person, in the right format and medium, at the right time. Sometimes referred
to as: Enterprise Information Management, Information resources management, or Business
intelligence, especially in connection with relevant software. See also: Information literacy,
Information
scientist,
Information
system,
Knowledge
management.
www.quantum3.co.za/CI%20Glossary.htm
the procedure of collecting data and processing, presenting and communicating information
en.wikibooks.org/wiki/SA_NCS_Computer_Application_Technology:Glossary
The provision of relevant information to the right person at the right time in a usable form to facilitate
situational understanding and decision making. It uses procedures and information systems to collect,
process,
store,
display,
and
disseminate
information.
(FM
3-0)
https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/7422-1/fm/313/glos.htm;jsessionid=MvnFH3yTHgWVsbGdH1zbk0Jyx82JCpBghJJlnpvwQhY51vkgrgQQ!74318
302
The planning, budgeting, manipulating, and controlling of information throughout its life cycle.
www.stanlake.co.uk/recruitment-candidates/recruitment-glossary.php
The entire process of defining, evaluating, protecting, and distributing data within an organization. ...
www.storsoftcorp.com/Glossary.htm
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
http://www.gichd.org/fileadmin/user_uplo
ad/i
mages/operational_assistance_res/IMSMA/I
nfo rmation_management_cycl.jpg
Diagra
m1
http://informationr.net/ir/4-3/p57fig1.gif
Diagra
m2
KEY TERMS USED IN
INFORMATION MANAGEMENT

Fields:
field is a named unit
of information. Each entry in a database can
have multiple fields of multiple types e.g. a
text field called 'favourite color' which
allows you to type in your favourite
shade, or a menu called
'Parish' that lets you choose one from a list of the
parishes that make up the country. By combining
several fields with appropriate names and types you
should be able to capture all the relevant information
about the items in your database.

Records:
In the context of a relational
database, a row—also called a record or tuple—
represents a single, implicitly structured data item in a
table. In simple terms, a database table can be thought
of as consisting of rows and columns or fields. Each
row in a table represents a set of related data, and
every row in the table has the same structure.

Tables: a collection of several records that
are related each other.
Table
information
are normally arranged in a logical manner. The
Personal Table in a Database might contain the fields:
Person ID, Surname, Christian Name, Street Address,
Town, Date of Birth, Registration Fee, etc. and
this contains several related fields that communicate
information about a set of records when looked at as
one picture.
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
A database is a collection of data that you want to manage, rearrange, and add to later. It is a good
program to use to manage lists that are not entirely numbers, such as addresses and phone numbers,
inventories, and membership rosters. With a database you could sort the data by name or city or postal
code or by any individual item of information recorded. You can create forms to enter or update or just
display the data. You can create reports that show just the data you are interested in, like members who
owe dues.
Both spreadsheets and databases can be used to handle much the same information, but each is optimized
to handle a different type most efficiently. The larger the number of records, the more important the
differences are.
Examples of databases: MS Access, dBase, FoxPro, Paradox, Approach, Oracle, Open Office Base.
Purpose:
Managing
data
Major Advantages: Can change way data is sorted and displayed
Features/Terms:
A flat database contains files which contain records which contain fields
A relational database contains tables which are linked together. Each table contains records which
contain fields. A query can filter your records to show just the ones that meet certain criteria or to
arrange them in a particular order.
Database: A Computer Database is a structured collection of records or data that is stored in a computer
system. The structure is achieved by organizing the data according to a database model. The model in
most common use today is the relational model. Other models such as the hierarchical model and the
network model use a more explicit representation of relationships (see below for explanation of the
various database models).
A computer database relies upon software to organize the storage of data. This software is known as a
database management system (DBMS). Database management systems are categorized according to the
database model that they support. The model tends to determine the query languages that are available to
access the database. A great deal of the internal engineering of a DBMS, however, is independent of the
data model, and is concerned with managing factors such as performance, concurrency, integrity, and
recovery from hardware failures. In these areas there are large differences between products.
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
http://en.wikipedia.org/wiki/Database
Hierarchical Model
In a hierarchical model, data is organized into an inverted tree-like structure, implying a multiple
downward link in each node to describe the nesting, and a sort field to keep the records in a particular
order in each same-level list. This structure arranges the various data elements in a hierarchy and helps to
establish logical relationships among data elements of multiple files. Each unit in the model is a record
which is also known as a node. In such a model, each record on one level can be related to multiple
records on the next lower level. A record that has subsidiary records is called a parent and the subsidiary
records are called children. Data elements in this model are well suited for one-to-many relationships with
other data elements in the database.
This model is advantageous when the data elements are inherently hierarchical. The disadvantage is that in
order to prepare the database it becomes necessary to identify the requisite groups of files that are to be
logically integrated. Hence, a hierarchical data model may not always be flexible enough to accommodate
the dynamic needs of an organization.
Network Model
In the network model, records can participate in any number of named relationships. Each relationship
associates a record of one type (called the owner) with multiple records of another type (called the
member). These relationships (somewhat confusingly) are called sets. For example a student might be a
member of one set whose owner is the course they are studying, and a member of another set whose
owner is the college they belong to. At the same time the student might be the owner of a set of email
addresses, and owner of another set containing phone numbers. The main difference between the network
model and hierarchical model is that in a network model, a child can have a number of parents whereas in
a hierarchical model, a child can have only one parent. The hierarchical model is therefore a subset of the
network model.
Programmatic access to network databases is traditionally by means of a navigational data manipulation
language, in which programmers navigate from a current record to other related records using verbs such
as find owner, find next, and find prior. The most common example of such an interface is the COBOLbased Data Manipulation Language defined by CODASYL.
Network databases are traditionally implemented by using chains of pointers between related records.
These pointers can be node numbers or disk addresses.
The network model became popular because it provided considerable flexibility in modelling complex
data relationships, and also offered high performance by virtue of the fact that the access verbs used by
programmers mapped directly to pointer-following in the implementation.
However, the model had several disadvantages. Navigational programming proved error-prone as data
models became more complex, and small changes to the data structure could require changes to many
programs. Also, because of the use of physical pointers, operations such as database loading and
CAPE Information Technology
Unit 2
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restructuring could be very time-consuming.
CAPE Information Technology
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Advantages


Fast
Efficient
Disadvantages
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Inflexible
Technically obsolete (although many in commercial use).
Relational model
The basic data structure of the relational model is a table where information about a particular entity (say,
employees) is represented in columns and rows. The columns enumerate the various attributes of an entity
(e.g. employee_name, address, phone_number). Rows (also called records) represent instances of an entity
(e.g. specific employees).
The "relation" in "relational database" comes from the mathematical notion of relations from the field of
set theory. A relation is a set of tuples, so rows are sometimes called tuples. All tables in a relational
database adhere to three basic rules.
The ordering of columns is immaterial. Identical rows are not allowed in a table.
Each row has a single (separate) value for each of its columns (each tuple has an atomic value).
If the same value occurs in two different records (from the same table or different tables) it can imply a
relationship between those records. Relationships between records are often categorized by their
cardinality (1:1, (0), 1:M, M:M).
Tables can have a designated column or set of columns that act as a "key" to select rows from that table
with the same or similar key values. A "primary key" is a key that has a unique value for each row in the
table. Keys are commonly used to join or combine data from two or more tables. For example, an
employee table may contain a column named address which contains a value that matches the key of an
address table. Keys are also critical in the creation of indexes, which facilitate fast retrieval of data from
large tables. It is not necessary to define all the keys in advance; a column can be used as a key even if it
was not originally intended to be one.
Advantages
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Overwhelmingly, the most popular type of DBMS in use and as a result technical development effort
ensures that advances e.g. object orientation, web serving etc appear quickly and reliably.
There are many, many third party tools such as report writers that are tuned to work with the popular
Relational DBMS via standards such as Open Database Connectivity (ODBC).
Offer distributed database and distributed processing options which might be advantageous for some
large consortium libraries.
Extremely well developed management tools and security with automatic data logging and recovery.
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1

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Have Referential integrity controls ensure data consistency.
Have Transactional integrity features to ensure that incomplete transactions do not occur.
Disadvantages
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
In the early days they were slow - Relational DBMS have to employ many tables to conform
absolutely to the various normalisation rules. This can make them slow and resource hungry compared
to more flexible (less rigorous?) systems. Most Relational DBMS do not now have performance
problems.
Some restrictions in field lengths. Field lengths are usually defined with a maximum. This can lead to
occasional practical problems e.g. a publisher with a 300 character name - they are rare but it can
happen!

SQL does not provide an efficient way to browse alphabetically through an index. Thus some
systems cannot provide a simple title A-Z browse.
http://www.biblio-tech.com/html/databases.html
Database Management System
A DBMS is a complex set of software programs that controls the organization, storage, management, and
retrieval of data in a database. DBMS are categorized according to their data structures or types. It is a set
of prewritten programs that are used to store, update and retrieve a Database. A DBMS includes:
1. A modeling language to define the schema of each database hosted in the DBMS, according to the
DBMS data model.
o The four most common types of organizations are the hierarchical, network, relational and
object models. Inverted lists and other methods are also used. A given database management
system may provide one or more of the four models. The optimal structure depends on the
natural organization of the application's data, and on the application's requirements (which
include transaction rate (speed), reliability, maintainability, scalability, and cost).
o The dominant model in use today is the ad hoc one embedded in SQL, despite the objections of
purists who believe this model is a corruption of the relational model, since it violates several
of its fundamental principles for the sake of practicality and performance. Many DBMSs also
support the Open Database Connectivity API that supports a standard way for programmers to
access the DBMS.
Data structures (fields, records, files and objects) optimized to deal with very large amounts of data stored
on a permanent data storage device (which implies relatively slow access compared to volatile main
memory).
A database query language and report writer to allow users to interactively interrogate the database,
analyze its data and update it according to the users privileges on data.
It also controls the security of the database.
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
CAPE NOTES Unit 2 Module 1 Content 1 - 3
6
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
Data security prevents unauthorized users from viewing or updating the database. Using
passwords, users are allowed access to the entire database or subsets of it called
subschemas. For example, an employee database can contain all the data about an individual
employee, but one group of users may be authorized to view only payroll data, while others
are allowed access to only work history and medical data.
If the DBMS provides a way to interactively enter and update the database, as well as
interrogate it, this capability allows for managing personal databases. However, it may not
leave an audit trail of actions or provide the kinds of controls necessary in a multi-user
organization. These controls are only available when a set of application programs are
customized for each data entry and updating function.
A transaction mechanism, that ideally would guarantee the ACID properties, in order to
ensure data integrity, despite concurrent user accesses (concurrency control), and faults (fault
tolerance).
It also maintains the integrity of the data in
the database.
The DBMS can maintain the integrity of the database by not allowing more than one user to
update the same record at the same time. The DBMS can help prevent duplicate records via
unique index constraints; for example, no two customers with the same customer numbers
(key fields) can be entered into the database. See ACID properties for more information
(Redundancy avoidance).
The DBMS accepts requests for data from the application program and instructs the
operating system to transfer the appropriate data.
When a DBMS is used, information systems can be changed much more easily as the
organization's information requirements change. New categories of data can be added to the
database without disruption to the existing system.
Organizations may use one kind of DBMS for daily transaction processing and then move the
detail onto another computer that uses another DBMS better suited for random inquiries
and analysis. Overall systems design decisions are performed by data administrators and
systems analysts. Detailed database design is performed by database administrators.
Database servers are specially designed computers that hold the actual databases and run only
the DBMS and related software. Database servers are usually multiprocessor computers, with
RAID disk arrays used for stable storage. Connected to one or more servers via a highspeed channel, hardware database accelerators are also used in large volume transaction
processing environments.
DBMSs are found at the heart of most database applications. Sometimes DBMSs are built
around a private multitasking kernel with built-in networking support although nowadays
these functions are left to the operating system.
CAPE Information Technology
Unit 2
Module 1 Specific Objective 1
Useful links
http://en.wikipedia.org/wiki/Database