Question

2. What are the advantages of database systems and database management? Discuss based on Data Independence, data modeling, Managing Structured, Semi-Structured, and Unstructured Data, Managing Data Redundancy, Specifying Integrity Rules, concurrency control, Backup and Recovery Facilities, Data Security, Performance Utilities. Use 3 of your own examples in your own words!!!

Answer 1

A Database Management System (DBMS) is defined as the software system that allows users to define, create, maintain and control access to the database.

advantages of Database Management System

Data Independence
Data Independence is defined as a property of DBMS that helps you to change the Database schema at one level of a database system without requiring to change the schema at the next higher level. Data independence helps you to keep data separated from all programs that make use of it.

You can use this stored data for computing and presentation. In many systems, data independence is an essential function for components of the system.
In DBMS there are two types of data independence

Physical data independence
Logical data independence

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data modeling
Data modeling (data modelling) is the process of creating a data model for the data to be stored in a Database. This data model is a conceptual representation of Data objects, the associations between different data objects and the rules. Data modeling helps in the visual representation of data and enforces business rules, regulatory compliances, and government policies on the data. Data Models ensure consistency in naming conventions, default values, semantics, security while ensuring quality of the data.

The main goal of a designing data model is to make certain that data objects offered by the functional team are represented accurately.
The data model should be detailed enough to be used for building the physical database.
The information in the data model can be used for defining the relationship between tables, primary and foreign keys, and stored procedures.

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Managing Structured
The Management System of a Database acts as an interface between the user and the database. The user requests the DBMS to perform various operations viz., insert, delete, update and retrieve data. Various components which perform these operations on the database constitute the structure of the DBMS.

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Semi-Structured and Unstructured Data
Semi-structured data is information that does not reside in a relational database but that have some organizational properties that make it easier to analyze. With some process, you can store them in the relation database (it could be very hard for some kind of semi-structured data), but Semi-structured exist to ease space. Example: XML data.

Unstructured data is a data that is which is not organized in a pre-defined manner or does not have a pre-defined data model, thus it is not a good fit for a mainstream relational database. So for Unstructured data, there are alternative platforms for storing and managing, it is increasingly prevalent in IT systems and is used by organizations in a variety of business intelligence and analytics applications. Example: Word, PDF, Text, Media logs.

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Managing Data Redundancy
The file based data management systems contained multiple files that were stored in many different locations in a system or even across multiple systems. Because of this, there were sometimes multiple copies of the same file which lead to data redundancy.

This is prevented in a database as there is a single database and any change in it is reflected immediately. Because of this, there is no chance of encountering duplicate data.

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Specifying Integrity Rules
Integrity constraints are a set of rules. It is used to maintain the quality of information.
Integrity constraints ensure that the data insertion, updating, and other processes have to be performed in such a way that data integrity is not affected.
Thus, integrity constraint is used to guard against accidental damage to the database

Domain constraints
Domain constraints can be defined as the definition of a valid set of values for an attribute.
The data type of domain includes string, character, integer, time, date, currency, etc. The value of the attribute must be available in the corresponding domain

Entity integrity constraints
The entity integrity constraint states that primary key value can't be null.
This is because the primary key value is used to identify individual rows in relation and if the primary key has a null value, then we can't identify those rows.
A table can contain a null value other than the primary key field.

Referential Integrity Constraints
A referential integrity constraint is specified between two tables.
In the Referential integrity constraints, if a foreign key in Table 1 refers to the Primary Key of Table 2, then every value of the Foreign Key in Table 1 must be null or be available in Table 2.

Key constraints
Keys are the entity set that is used to identify an entity within its entity set uniquely.
An entity set can have multiple keys, but out of which one key will be the primary key. A primary key can contain a unique and null value in the relational table.

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concurrency control
Concurrency Control deals with interleaved execution of more than one transaction. In the next article, we will see what is serializability and how to find whether a schedule is serializable or not.

Concurrency control protocols ensure atomicity, isolation, and serializability of concurrent transactions. The concurrency control protocol can be divided into three categories:
Lock based protocol
Time-stamp protocol
Validation based protocol

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Backup and Recovery Facilities
Database Management System automatically takes care of backup and recovery. The users don't need to backup data periodically because this is taken care of by the DBMS. Moreover, it also restores the database after a crash or system failure to its previous condition.

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Data Security
Data Security is vital concept in a database. Only authorised users should be allowed to access the database and their identity should be authenticated using a username and password. Unauthorised users should not be allowed to access the database under any circumstances as it violates the integrity constraints.

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Performance Utilities
Loading : A loading utility is used to load existing data files-such as text files or sequential files-into the database. Usually, the current (source) format of the data file and the desired (target) database file structure are specified to the utility, which then automatically reformats the data and stores it in the database. With the proliferation of DBMSs, transferring data from one DBMS to another is becoming common in many organizations. Some vendors are offering products that generate the appropriate loading programs, given the existing source and target database storage descriptions (internal schemas). Such tools are also called conversion tools.

Backup: A backup utility creates a backup copy of the database, usually by dumping the entire database onto tape. The backup copy can be used to restore the database in case of catastrophic failure. Incremental backups are also often used, where only changes since the previous backup are recorded. Incremental backup is more complex but saves space.

File Reorganization: This utility can be used to reorganize a database file into a different file organization to improve performance.
Performance Monitoring: Such a utility monitors database usage and provides statistics to the DBA. The DBA uses the statistics in making decisions such as whether or not to reorganize files to improve performance.