Articles

The Evolution of Database

In Database Systems on October 18, 2010 by Muhammad Haadi

From pre-stage flat-file system, to relational and object-relational systems, database technology has gone through several generations and its history that is spread over more than 40 years now.

The Evolution :

1968 File-Based: predecessor of database, Data was maintained in a flat file.

Flat Files:

Earlier, punched cards technology was used to store data – later, files. But the files have no as such advantage, rather have several limitations.

 

Advantages Limitations
Various access methods , e.g., sequential, indexed, random Requires extensive programming in third-generation language such as COBOL, BASIC.
Separation and isolation: Each program maintains its own set of data, users of one program may not be aware of holding or blocking by other programs that are being used somewhere else, by another user.
Duplication of data – same data is held by different programs, thus, wastes space and resources.
High maintenance costs such as ensuing data consistency and controlling access
Sharing granularity is very coarse.
Weak security.

 

Note: The distinction of storing data in files and databases is that databases are intended to be used by multiple programs and types of users.

 

 

[1968-1980] Era of Hierarchical Database: Prominent hierarchical database model was IBM’s first DBMS called IMS (Information Management System).

Hierarchical Data Model:

Mid 1960s Rockwell collaborates with IBM to create the Information Management System (IMS), IMS lead the mainframe database market in 70’s and early 80’s.

In this model, files are related in a parent/child manner, with each child file having at most one parent file.

 

Advantages Limitations
Efficient searching. Complex implementation
Less redundant data. Difficult to manage and lack of standards, can’t easily handle many-many relationships.
Data independence. Lacks structural independence.
Database security and integrity.

 

 

Network Data Model:

Early 1960s, Charles Bachmann developed first DBMS at Honeywell, Integrated Data Store (IDS)

It standardized in 1971 by the CODASYL group (Conference on Data Systems Languages).

In Network data model, files are related as owners and members, similar to the common network model except that each member file can have more than one owner.

Network data model identified the following three database components:

  1. Network schema—database organization[structure]
  2. Sub-schema—view s of database per user
  3. Data management language — at low level , procedural

 

Advantages Limitations
Ability to handle more relationship types System complexity and difficult to design and maintain
Ease of data access Lack of structural independence as data access method is navigational.
Data Integrity
Data Independence

 

Prominent network database model was CODASYL DBTG model where as IDMS was the most popular network DBMS.

Here, I am clearly mentioning one thing that the Hierarchical Model and the Network Model were in use in almost the same era.

 

[1970-present] Era of Relational Database and Database Management: The relational database model was conceived by E. F. Codd in 1970. It can be defined using the following two terminologies:

  1. Instance – a table with rows or columns.
  2. Schema – specifies the structure (name of relation, name and type of each column)

The model is based on branches of mathematics called set theory and predicate logic.

Relational DBMS at a glance:


 

General Comparison:

Here is a glimpse of all those database models we have discussed till now.

 

 

Object Oriented Database Model:

It supports the modeling and creation of the data as objects.

 

Advantages Limitations
Can efficiently manage a large number of different data types. Switching an existing database to OODBMS requires an entire change from scratch.
Objects with complex behaviors are easy to handle using inheritance and polymorphism etc. An OODBMS is typically tied to a specific programming language and an API; this reduces its flexibility.
Reduces the large number of relations by creating objects. Ad-hoc queries are difficult to implement as one cannot join two classes as one can join two tables in RDBMS. Therefore, queries depend upon the design of the system.
Creates problems when deleting data in bulk.

 

 

Object Relational Database Model:

Object relational databases span the object and relational concepts.

 

Advantages Limitations
Large storage capacity The architecture of the object relational model is not appropriate for web applications.
High access speed

 

Let’s take a fleeting look at the history.

1970: Ted Codd at IBM’s San Jose Lab proposed relational models.

Two major projects start and both were operational in late 1970s

INGRES at University of California, Berkeley became commercial and followed up POSTGRES which was incorporated into Informix.

System R at IBM san Jose Lab, later evolved into DB2, which became one of the first DBMS product based on the relational model. (Oracle produced a similar product just prior to DB2.)

1976: Peter Chen defined the Entity-relationship(ER) model

1980s: Maturation of the relational database technology, more relational based DBMS were developed and SQL standard adopted by ISO and ANSI.

1985: Object-oriented DBMS (OODBMS) develops.

1990s: Incorporation of object-orientation in relational DBMSs, new application areas, such as data warehousing and OLAP, web and Internet, Interest in text and multimedia, enterprise resource planning (ERP) and management resource planning (MRP)

1991: Microsoft ships access, a personal DBMS created as element of Windows gradually supplanted all other personal DBMS products.

1995: First Internet database applications

1997: XML applied to database processing, which solves long-standing database problems.  Major vendors begin to integrate XML into DBMS products.

Figure 1 . Pictorial representation of Database Evolution over decades

 

Obviously, we cannot discuss all of the history material here, so if anyone wants to study more, here are the names of the models proposed up till now:

  1. Semantic [SIM: Semantic Information Manager]
  2. Multidimensional [MDDBMS]
  3. Associative
  4. Concept-Oriented [CODM: Concept-Oriented Data Model] etc.
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15 Responses to “The Evolution of Database”

  1. Dear Sir,

    I was searching for the history of the database that was useful for me impart knowledge to my students.I found it… give me more information.

    Rajiv

  2. Thanks for sharing.. The article was quite helpful for my assignment in the DBMS class. 🙂

  3. […] Haadi, “The Evolution of Database” All About Databases (October 18, […]

  4. What about document oriented databases?

  5. A comprehensive evolution account. Thank you.

  6. This article was really helpful to me.big up

  7. Is there an updated version of this article going on through XML, NoSQL and triplestores?

  8. This article helps provide a background to how we have arrived at this point. Thank you for posting.
    .

  9. quite helpful to my study on database

  10. Thanks Sir..very helpful.

  11. grateful for the article

  12. Hello Muhammad,

    Many thanks for sharing this information, it is very good to know how all of what we do has evolved.

    Best Regards,
    Kannan

  13. jazakumheri

  14. really helpfull

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