Data
Administrator (DA) and Database Administrator (DBA)
database administrators |
Both of these terms – Data administrator and Database
administrator – seem to be similar. Though they both are responsible for
managing database for an organization they both are different from each other
in their required skills and responsibilities.
The following sub-sections explore these concepts of data
administrator and database administrator.
Data administrator (DA)
“The data
administrator may be a person within the organization who controls the info of the database.”
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DA determines what data to be
stored in database supported requirements
of the organization.
DA is involved more within the requirements gathering, analysis, and style phases.
DA may be a manager or some senior level person in a corporation who understands organizational requirements with reference to data.
DA doesn't got to be a technical person, but any quite knowledge about database technology are often more beneficiary.
DA is involved more within the requirements gathering, analysis, and style phases.
DA may be a manager or some senior level person in a corporation who understands organizational requirements with reference to data.
DA doesn't got to be a technical person, but any quite knowledge about database technology are often more beneficiary.
In short, DA is a business focused person, but, he/she
should understand more about the database technology.
Database administrator (DBA)
“The
database administrator may be a person within the organization who controls the planning and therefore
the use of the database.”
DBA provides necessary
technical support for implementing a database.
DBA is involved more within the design, development, testing and operational phases.
DBA may be a technical person having knowledge of database technology.
DBA doesn't got to be a business person, but any quite knowledge about an functionality of a corporation are often more beneficiary.
DBA is involved more within the design, development, testing and operational phases.
DBA may be a technical person having knowledge of database technology.
DBA doesn't got to be a business person, but any quite knowledge about an functionality of a corporation are often more beneficiary.
In short, DBA is a technically focused person, but, he/she
should understand more about the business to administer the databases
effectively.
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Functions and Responsibilities of DBAs.
1.
Schema definition :
The DBA
defines the logical schema of the database. A schema refers to the general logical structure of the database.
According to this schema database are going to be developed to store required data for a corporation .
According to this schema database are going to be developed to store required data for a corporation .
2.
Storage structure and access method
definition :
The DBA
decides how the info is to be
represented within the stored database.
Based on this, storage structure of the database and access methods of knowledge is defined.
Based on this, storage structure of the database and access methods of knowledge is defined.
3.
Assisting application programmers :
The DBA provides assistance to application
programmers to develop application programs.
4.
Physical organization modification :
The DBA
modifies the physical organization of the database to reflect the changing
needs of the organization or to enhance performance.
5.
Approving data access :
The DBA
determines which user needs access to which a part
of the database.
According to this, various sorts of authorizations are granted to different users. this is often required to stop unauthorized access of a database.
According to this, various sorts of authorizations are granted to different users. this is often required to stop unauthorized access of a database.
6.
Monitoring performance :
The DBA monitors performance of the system.
The DBA ensures that better performance is maintained by making changes in
physical or logical schema if required.
7.
Backup and Recovery
Database may be a valuable asset for any organization.
It shouldn't be lost or damaged.
The DBA ensures this by periodically backing up the database on magnetic tapes or remote servers. just in case of failures, like flood or virus attack, database is recovered from this backup
The DBA ensures this by periodically backing up the database on magnetic tapes or remote servers. just in case of failures, like flood or virus attack, database is recovered from this backup
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Data
warehouse
Data stored in databases can be one of the two types: first,
operational data, which is used in day-to-day operations; and second, decision
making data, which is used occasionally to make decisions.
“A data warehouse may be
a decision support database that's maintained
separately from the organization’s operational database.”
Data stored in data warehouse possess following
characteristics:
1.
Subject-oriented
2.
Integrated
3.
Time-variant
4.
Non-volatile
These characteristics are described below:
Subject-oriented
Data warehouse is organized around the manor subjects or
topics of an organization.
These subjects are those for which there may be a need to
take some decision. For example, customers, products, sales etc.
Integrated
Data to be stored in a data warehouse might be coming from
different locations, such as from different branches of a company or bank.
It is also possible that this data may have different
structures according to their source.
All such kind of data is integrated in data warehouse. This
means, it is converted to some homogenous structure.
Time-variant
Data warehouse provides information from a historical
perspective.
Data stored in data warehouse contains time element to
reflect timing of the data.
So, data in data warehouse indicates what happened previous
day, last week, last month, during past two years and so on.
Non-volatile
Data stored in data warehouse is never deleted or updated.
New data is always added as a supplement to the database on a regular basis.
Data
dictionary :
Data dictionary or data directory is a file that contains
metadata.
Data dictionary is typically a neighborhood of
the system catalog that's generated for every database.
Data dictionary stores and manages following types of
information.
Description of the schema, i.e. overall logical structure,
of the database. This can involve information such as table names, owners,
column names, data types, size, and constraints.
Detailed information of physical database design, such as
storage structures, access paths, and field & record size.
Description of the database users, their responsibilities
& access rights.
Descriptions of the database transactions, i.e. operations
performed on database.
Relationships between transaction and data items to
determine which transaction are affected when certain data definitions are
changed.
Relationships among entities, such as, which account belongs
to which branch in a banking system.
Usage statistics, such as frequencies of queries &
transactions.
Access counts to different parts of the database.
Components of data dictionaries
A data dictionary contains the following components:
1.
Entities
2.
Attributes
3.
Relationships
4.
Key
These components are described below:
Entities:
“An entity is a ‘thing’ or ‘object’
existing in the real world that is distinguishable from all other objects.”
An entity represents an object in which user is interested.
In other words, an entity represents any item about which information is
stored.
For example, any particular customer, say ‘Riya’, or some
particular account, say ‘A01’, can be considered as an entity.
Attributes:
An attribute may be a property or characteristic of an entity.
For example, customer id, name, address, contact numbers are
attributes of entity customer. Similarly, account number, balance, branch name
are attributes of entity account.
Relationships:
A relationship is an association or connection among
entities.
For example, an association between some account, say ‘A01’,
and branch, say ‘anand’ is referred as relationship.
Key:
A data item or a field, which is used to identify a record
in a database, is referred as key.
A primary key's wont to uniquely
identify a record. For example, customer id acts as a primary key for
customers.
When more than one field is used to identify a record, it is
called concatenated key. For example, customer id & name are concatenated
key for customer.
Active and Passive Data Dictionaries:
Data dictionaries can be either active or passive as
explained below:
Active data dictionary:
If data dictionary is managed automatically by database
management software, it is called an active data dictionary.
It is also called integrated data dictionary.
It is always consistent with the current definition and
structure of the database. Because, it is managed by database system itself.
Passive data dictionary:
If data dictionary is managed by the user of the system, it
is called a passive data dictionary.
It is also called non-integrated data dictionary.
It may not be consistent with the current
definition and structure of the database. Because, it requires explicit changes
whenever structure of the database changes.
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