0:01	foreign
0:06	we will see about database administrator
0:10	simply referred as DBA in the last
0:13	presentation we have seen four different
0:15	types of users the first one the naive
0:18	users the second one application
0:20
programmers the third one sophisticated
0:23
users and the last one specialized users
0:25
and we have learned about all these
0:28
users in the previous presentation in
0:30
this presentation we are going to
0:31
exclusively focus on the undeniable user
0:34
as far as database systems are concerned
0:37
the database administrator let's see the
0:40
basics about the database administrator
0:42
any organization that uses database will
0:45
certainly have a database administrator
0:47
because the database administrator he or
0:50
she is the one who has the complete
0:52
control over the database it means the
0:55
database administrator has the central
0:56
control over the data and the set of
0:59
programs those access those data so
1:02
without database administrator it's
1:04
practically not possible to gain access
1:06
over the database management system and
1:09
as mentioned this database administrator
1:11
has the central control over such system
1:14
and when we say that this database
1:16
administrator has the central control
1:18
over the database system then obviously
1:20
the key role will be having the complete
1:22
privilege so he is the one who decides
1:25
everything with respect to the databases
1:27
now let's see the various functions of
1:29
database administrator the primary
1:31
function of database administrator is he
1:34
is the one who defines the schema I mean
1:36
the schema definition what do we mean by
1:39
this when we have a database we know
1:41
this database is a collection of
1:43
interrelated data in the form of tables
1:45
say for example in SQL if we want to
1:48
create a table we have ddl commands
1:50
right who is going to execute this ddl
1:52
who is going to define the structure of
1:54
the database the overall design of the
1:56
database the schema definition the
1:58
tables and the columns
2:00
it's the database administrator
2:02
obviously he is the one who is
2:04
authorized to use data definition
2:06
language ddl and when he creates a table
2:10
when he manages the table obviously he
2:13
is the one who decides the storage
2:14
structure and the access method
2:16
definition because databases needs to be
2:19
stored in the physical medium so
2:21
database administrator will have the
2:23
complete control over the storage
2:25
structure and also the access method how
2:28
the data can be accessed which mode of
2:30
access is permitted and which mode of
2:32
access is not permitted and coming to
2:34
the third function of database
2:36
administrator he is the one who can do
2:38
modifications in the schema as well as
2:41
the physical organization modification
2:43
if you are directly watching this
2:44
lecture without knowing the basics of
2:46
schema and instances I request you to
2:49
watch my previous lecture titled
2:50
instances and schema so that you will
2:53
gain better understanding about schemas
2:54
and instances so when we talk about
2:56
schema it's the overall design of the
2:59
database so when any modification is
3:01
required on the schema then database
3:04
administrator only can do that and also
3:06
if there are any physical organization
3:08
modification it means the organization
3:10
of data in the storage level and that is
3:13
also done by the database administrator
3:15
and coming to the fourth function of the
3:17
database administrator he is the one who
3:20
is involved in granting of authorization
3:22
for data access let's take banking as an
3:25
example we know very well in database
3:27
management system the database is the
3:29
central unit that stores all the data in
3:32
the form of tables and we have a
3:34
collection of tables which we describe
3:35
as a database when we have a database
3:38
all the users whoever wants to access
3:40
the data they will be getting the data
3:43
only from the database it's not the data
3:45
that is distributed across every user's
3:48
machine because database is a central
3:50
unit all data are stored in one place
3:52
and the complete database is actually
3:54
maintained by the database administrator
3:57
now database administrator is the one
3:59
who grants Privileges and grants
4:01
authorization for data access to the
4:03
users he is the one who decides what all
4:06
the data that a teller can access what
4:08
all the data a clerk can access what
4:10
data a manager can access and what data
4:13
an end user can access in simple terms
4:16
authorization means who can access what
4:18
and this is decided by the database
4:21
administrator and coming to the next
4:23
privilege he is the one who should
4:25
involve in the routine maintenance
4:26
activities what are all the routine
4:28
maintenance activities that a database
4:30
administrator should focus on the first
4:32
one is the periodic backup taking backup
4:35
of the database is very very important
4:37
we know any system is subject to failure
4:40
it may be a hardware system or it may be
4:42
a software system a database software
4:44
may also crash and we know the databases
4:47
are installed on the physical medium
4:48
maybe an hard disk or an SSD or even a
4:51
storage server after all they are
4:53
physical devices which may undergo
4:55
failure at any point of time what if the
4:58
physical medium or the storage device is
5:00
encounter failure obviously the data
5:03
present in the database will not be
5:04
accessible so when we have a backup
5:07
obviously we can restore the data let's
5:09
assume there is a Data Center and all
5:11
the data are stored in that data center
5:13
and there are no problems with the
5:15
hardware there are no problems with the
5:17
software with respect to the hardware
5:19
and software everything is fine who
5:21
knows the data center could be affected
5:23
due to natural calamities the data
5:25
center could be affected by floods or
5:28
earthquakes in that case taking a backup
5:30
and storing it in a remote location is
5:32
always essential and this is one of the
5:35
jobs of the database administrator to
5:37
take periodic backups not only for the
5:39
sake of retrieving the data due to
5:41
Hardware or software failures even due
5:43
to natural disasters and coming to the
5:46
next routine activity he's the one who
5:48
should always check the disk space why
5:51
the database administrator should
5:52
indulge in disk phase management let's
5:54
assume at this instant the database is
5:57
containing the records of 1000 users and
5:59
if company started advertising their
6:01
product if new customers are added in
6:04
one day thousands and thousands of
6:06
customers can become a new customer for
6:08
our organization and we know databases
6:11
are obviously stored in the physical
6:12
medium the physical devices it may be a
6:15
hard disk or any storage device or even
6:17
a storage server and what happens if new
6:19
customer information are added to the
6:21
database obviously it increases the
6:23
storage size isn't it he's the one who
6:25
should periodically check whether proper
6:27
disk space is available for all the data
6:29
and coming to the last routine activity
6:32
he should also focus on the performance
6:34
just imagine we are going to an ATM
6:37	machine to withdraw the money after
6:38	inserting the card after giving all the
6:40	information if the system takes so much
6:43	of time to respond or to retrieve the
6:45	data from the database and present it to
6:47	us obviously it's not good right so
6:49	databases must respond to the queries as
6:52	quick as possible and also these
6:54	databases are stored in the hardware and
6:56	periodically the database administrator
6:58	to check the performance of the database
7:00	so that he can ensure all is well from
7:02	his side and users are also getting the
7:04	data access without delays so far we
7:07	have seen what is the role of database
7:09	administrator and the various functions
7:11	of database administrator I'll see you
7:14	in the next presentation and thank you
7:16	for watching
7:17	[Applause]
7:19	[Music]