by Dinesh Thakur Category: DBMS & RDBMS

The E-R model can result problems due to limitations in the way the entities are related in the relational databases. These problems are called connection traps. These problems often occur due to a misinterpretation of the meaning of certain relationships.

 
by Dinesh Thakur Category: DBMS & RDBMS

When multiple transactions are trying to access the same sharable resource, there could arise many problems if the access control is not done properly. There are some important mechanisms to which access control can be maintained. Earlier we talked about theoretical concepts like serializability, but the practical concept of this can be implemented by using Locks and Timestamps.

 
by Dinesh Thakur Category: DBMS & RDBMS

There is no standard for representing data objects in ER diagrams. Each modeling methodology uses its own notation.

All notational styles represent entities as rectangular boxes and relationships as lines connecting boxes. Each style uses a special set of symbols to represent the cardinality of connection. The symbols used for the basic ER constructs are:

 
by Dinesh Thakur Category: DBMS & RDBMS

In Entity-Relationship model a database is modeled as a collection of entities and relationship among entities. The ER model views the real world as a construct of entities and association between entities.



 
by Dinesh Thakur Category: DBMS & RDBMS

The related information when placed is an organized form makes a database. In simple words, an organized collection of related information is known as database. The organization of data/information is necessary because unorganized information has no meaning. There are so many examples of organized information, more precisely and the most common are, the dictionary, the telephone directory, student record register, your own address book and many more. In each of these the data is stored in some particular order i.e. in an organized form.



 
by Dinesh Thakur Category: DBMS & RDBMS

A database instance controls 0 or more databases. A database contains 0 or more database application schemas. A database application schema is the set of database objects that apply to a specific application. These objects are relational in nature, and are related to each other, within a database to serve a specific functionality. 



 
by Dinesh Thakur Category: DBMS & RDBMS

What is a Database View, A view can join information from several tables together, or we can say that Views are useful for Hiding unwanted information for example adding the ename field to the Order information. Database View is a subset of the database sorted and displayed in a particular way. A database view displays one or more database records on the same page. A view can display some or all of the database fields.



 
by Dinesh Thakur Category: DBMS & RDBMS

Any access to the stored data is done by the data manager. A user's request for data is-received by the data manager, which detern1ines the physical record required. The decision as 10 which physical record is needed may require some preliminary consultation of the database and/or the data dictionary prior to the access of the actual data itself.



 
by Dinesh Thakur Category: DBMS & RDBMS

A database object in a relational database is a data structure used to either store or reference data. The most common object that most people interact with is the table. Other objects are indexes, stored procedures, sequences, views and many more.



 
by Dinesh Thakur Category: DBMS & RDBMS

Attributes means characteristics. For instance, in a database or a spreadsheet you can apply attributes to each field or cell to customize your document. As a general attribute, you can choose whether it is to be a text field or a numeric field or perhaps a computed field, whose value the application calculates for you.



 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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