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00:00Introducing DBMS
00:02The concepts discussed in this table are
00:13Introduction to DBMS
00:15Relational Database Management System
00:18Levels of Database Implementation
00:20Data Independence
00:22Data Model
00:23Basics of Relational Model
00:26Different Types of Keys
00:27Views
00:29Recapitulation of the topic
00:31What do the following examples mean to you?
00:37They probably don't mean a great deal.
00:40They appear to be just a random set of words, letters and numbers
00:44and that is because they have no context.
00:48This is known as data.
00:51Data consists of raw facts and figures.
00:54In order to turn data into meaningful information,
00:58we need to process the data.
01:03Information is the data
01:05which has been processed within a context in order to give it meaning.
01:10Let's have a look at how the data can be turned into information.
01:17We started off with the raw data.
01:21At this stage, these are just numbers.
01:24The raw data is given a context.
01:27We are told that these numbers are test scores
01:31which were achieved by a group of students.
01:34However, even with a context, the data still needs to be processed in order to turn it into information.
01:43The processing in this case might be to calculate the average from the set of scores.
01:49It is the data as it represents a raw figure.
02:01Now, this is turned into the information as it is given a context and structure.
02:08Each piece of information about an entity, such as name of a person or address,
02:17age or name of a product or the price is a data item.
02:23A database is a well-organized collection of data
02:27that ensures safety, security and integrity of data.
02:32A properly designed database not only provides you with access to up-to-date
02:41but also accurate information.
02:45A correct design is vital to achieving your goals in working with a database.
02:52Let us see what we need for a good database design.
02:56A good database design is one that
03:03Divides your information into tables in order to reduce redundant data.
03:11It ensures the accuracy and integrity of your information.
03:17It enhances data processing and report generation.
03:21A database management system is a software that provides the essential services
03:31to create, manage and maintain the databases.
03:35Let's watch the following animation for better understanding.
03:41A database management system gives us tools to
03:46Store data in a structured way
03:49Query the database
03:51Sort and manipulate the data in the database
03:55Validate the data entered and check for inconsistencies
04:01Produce flexible reports
04:03Relational databases store data or information in tables
04:11A database table is much like a spreadsheet
04:15Where the data is stored in rows and columns
04:18For example, in the following table
04:22Each horizontal column represents a table record
04:26And each vertical column represents a table field
04:29A relational database is a type of database
04:35That organizes data into tables
04:38And links them based on defined relationships
04:42Systems comprising of databases and database management systems
04:49Are simply referred as database systems
04:53Some of the advantages of database systems are as follows
05:00Let us discuss some of the examples of popular database management systems
05:08MySQL is the most popular open source database management software
05:14PostgreSQL is also a powerful open source object relational database system
05:22Oracle is an object relational database management system produced by Oracle Corporation
05:30Aang is a commercially supported open source relational database management system
05:38DB2 is the database software that offers industry leading performance
05:44Scale and reliability on different platforms
05:48Microsoft SQL server is a relational web hosting database
05:56That is used to store website information like blog posts or user information
06:03Sybase offers a comprehensive set of database management technologies to work with the databases
06:10Now here is the time to test your knowledge
06:16Select the correct option for the given question
06:19A database management system provides three views of the database data
06:31The external level
06:33The conceptual level
06:33The conceptual level
06:35And the internal level
06:38Following animation will give detailed explanation of the various levels of database implementation
06:45The ability to modify a scheme definition in one level without affecting a scheme definition in a higher level is called data independence
06:58There are two types of data independence
07:03Logical independence and physical independence
07:07Logical independence is the ability to modify conceptual schema without causing application programs to be rewritten
07:16It is usually done when logical structure of database is altered
07:22In the given example, a view including only e-hash and name is not affected by changes in any other attributes
07:33Physical independence is the ability to modify the internal scheme without causing application programs to be rewritten
07:42Modifications at this level are usually to improve performance
07:48For example, creating additional access structure
07:52A data model is a way by which data structures and their relationships are analyzed
08:01The different data models are
08:04Relational data model
08:06Network data model
08:08And hierarchical data model
08:10In relational database terminology
08:15Relation is represented by table
08:17A table is a named collection of all occurrences of a given type of logical record
08:23To be a relation, it must satisfy following four conditions
08:30At every row-column intersection, there must be an atomic value
08:37That is, a value that cannot be further subdivided
08:41No duplicity
08:43No two rows of relation will be identical
08:47That is, in any two rows value, at least one column must be different
08:52Ordering of rows is immaterial
08:56Ordering of columns is immaterial
08:59A tuple is an ordered list of values
09:04The rows of tables are referred to as tuples
09:08The columns of relations are referred to as attributes
09:14A domain is a pool of values from which the actual values appearing in a given column are drawn
09:24The number of attributes in a relation
09:27The number of attributes in a relation determines the degree of a relation
09:31The number of tuples in a relation is called the cardinality of the relation
09:39Now, here is the time to test your knowledge
09:45Select the correct option for the given question
09:48A key is a set of one or more attributes
09:58Used to identify records uniquely in a relation or table
10:03The different types of keys are primary key, candidate key, alternate key and foreign key
10:12A primary key is a set of one or more attributes that uniquely identify a tuple or record within the relation
10:24It cannot contain any duplicate, blank or null value
10:28A candidate key is a combination of attributes inside a relation that serves as a primary key
10:38A relation can have multiple candidate keys
10:42Alternate key is a key other than the candidate key
10:49In other words, if there are two or more candidate keys then
10:54Only one of them serves as the primary key and the rest are called alternate keys
11:00Foreign key is a non-key attribute whose value is derived from the primary key of another table
11:09The table that defines primary key is called primary table or master table
11:18The table in which foreign key exists is called a foreign table or detail table
11:26Consider the two tables, customer's detail and order's detail
11:34Here, we can show the relations on the basis of the common field i.e. customer ID
11:41Now, here is the time to test your knowledge
11:46Select the correct option for the given question
11:49Referential integrity refers to the relationship between tables
11:57It is the logical dependency of a foreign key on a primary key of another table
12:03The integrity of a row that contains a foreign key depends on the integrity of the row that contains the matching primary key
12:12Referential integrity is a subset of data integrity which is concerned with the accuracy and consistency of all data
12:22Consider a database which contains two tables
12:28Customer detail table
12:29Order detail table
12:31To uniquely identify each customer in the customer detail table, a primary key column named customer ID is created
12:40To identify a customer and inventory relationship in the order detail table, an existing customer in the customer detail table must be referenced
12:51Thus, the customer ID column also created in the order detail table is a foreign key
12:57This column values must reference existing and identical values in the primary key column of another table
13:06Which is the customer ID column of the customer detail table
13:10Referential integrity is a standard that means any customer ID value in the customer detail table may not be edited without editing the corresponding value in the order detail table
13:23The following conditions are required to enforce referential integrity
13:30After you have enforced referential integrity, the following rules should be applied
13:38A view is a pseudo table or virtual table whose contents are taken from other tables depending upon a condition
13:48The syntax of the view is as follows
13:53Let us see an example of view
13:58Now, here is the time to test your knowledge
14:06Select the correct option for the given question
14:09Let us recapitulate the topic
14:20A database is an organized collection of data
14:23Data is stored in a relational database in one or more tables
14:29A group of rows and columns forms a table
14:33The horizontal subset of a table is known as a row or tuple
14:38The vertical subset of a table is known as a column or attribute
14:44A candidate key is an attribute or a set of attributes that uniquely identifies a row
14:53A primary key is one of the candidate keys
14:57Only one of the candidate keys is selected as the primary key of a table
15:03All other candidate keys are called alternate keys
15:08A non-key attribute whose value is derived from the primary key of another table is known as foreign key in its current table
15:18Referential integrity is the logical dependency of a foreign key on a primary key of another table
15:25Let us go through some project work
15:33Thank you