Relational Database ModelIt’s benefits & limitations

By Jatin Chhabra

Relational Database Model• Relational Database Model is a based on

tables and for management purposes. This model was invented by Edgar F. Codd in 1969. Edgar at that time was working at IBM. In the relational model of a database, all data is represented in terms of “tuples” & grouped into “relations”. A database organized in terms of the relational model is a relational database.

Table 1.1

• From S.no to Room rates is Attributes• From 1 to 7 is Tuple

S.no Hotel

City State Rooms

Front desk

Restaurant

Travel Desk

Parking

Room rate

1 ABC A AA 12 Yes Yes Yes No 10002 XYZ S DD 23 Yes Yes Yes Yes 20003 AAA D SS 34 Yes Yes Yes Yes 12004 CCC F FF 43 Yes Yes Yes Yes 23005 BBB G GG 12 Yes No Yes Yes 30006 DD

DH HH 32 Yes No No Yes 1000

7 FFF J JJ 45 No No No Yes 700

Benefits of Relation base model

Relational Database Model is widely used around the world, as its:1. Easy to use: In Relational model data is easily presented & visible. So revision becomes quite easy as the information is stored in simple tables & rows. Such data id find attractive for the first time user.2. Flexibility: An operator or a user can easily link & extract the data & can easily get the desired information easily.3. Precision: The usage of relational algebra and calculus in the manipulation of the relations between the tables ensures that there is

no ambiguity (doubtfulness or uncertainty), which mayotherwise come while establishing the links in a complicated network type database.4. Security: Security control & authorization can be implemented on various tables, which gives a sense of control to the creator of the table. If someone requires the protective data then she/he needs to have the permission from the creator.5. Data Independence: Data independence is achieved easily with normalization structure, used in a relational database than in the more complicated tree or network structure.

6. Data Manipulation Language: The possibility of responding to query by means of a language based on relational algebra and relational calculus e.g SQL is easy in the relational database approach. For data organized in other structure the query language either becomes complex or extremely limited in its capabilities.

Limitations of relational database model

1. Performance: A major constraint in the use of relational database system is machine performance. If there is an enormous data in the tables then the performance gets affected in responding to the sql queries.2. Physical Storage Consumption: With an interactive system, for example an operation like join would depend upon the physical storage also. It is, therefore common in relational databases to tune the databases and in such a case the physical data layout would be chosen so as to give good performance in the most frequently run

operations. It therefore would naturally result in the fact that thelays frequently run operations would tend to become even more shared.3. Slow extraction of meaning from data: If the data is naturally organized in a hierarchical manner and stored as such, the hierarchical approach may give quick meaning for that data.

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