RELATIONAL DATABASE MANAGEMENT SYSTEM

A relational database is a collection of information that organizes data points with defined relationships for easy access. In the relational database model, the data structure including data tables, indexes and views remain separate from the physical storage, allowing administrators to edit the physical data storage without affecting the logical data structure.

You’ll find that most databases used in businesses these days are relational databases, as opposed to a flat file or hierarchical database. Relational databases have the clout to handle multitudes of data and complex queries, whereas a flat file takes up more space and memory, and is less efficient. So modern databases use multiple tables as standard. The data is stored in lots and lots of tables, or ‘relations’. These tables are divided into rows (records) and columns (fields).

1. Manageability: for starters, an RDB is easy to manipulate. Each table of data can be updated without disrupting the others. You can also share certain sets of data with one group, but limit their access to others – such as confidential information about employees.
2. Flexibility: if you need to update your data, you only have to do it once – so no more having to change multiple files one at a time. And it’s pretty simple to extend your database. If your records are growing, a relational database is easily scalable to grow with your data.
3. Avoid Errors: there’s no room for mistakes in a relational database because it’s easy to check for mistakes against the data in other parts of the records. And since each piece of information is stored at a single point, you don’t have the problem of old versions of data clouding the picture.

CHALLENGES OF RELATIONAL DATABASE

1. Scalability: Because relational databases are built on a single server. This means, in order to scale, you’ll need to purchase more expensive hardware with more power, storage, and memory.
2. Performance: Rapid growth in volume, velocity, variety, and complexity of data creates even more complicated relationships. Relational databases tend to have a hard time keeping up, which can slow down performance.
3. Relationships: Relational databases don’t actually store relationships between elements, which makes understanding connections between your data reliant on other joins.

Advantages of DBMS: 

1. Data Independence.

 2. Efficient Data Access.

 3. Data Integrity and security.

 4. Data administration.

 5. Concurrent access and Crash recovery.

 6. Reduced Application Development

What is a Record or a Row?

A record is also called as a row of data is each individual entry that exists in a table. For example 

What is a column?

A column is a vertical entity in a table that contains all information associated with a specific field in a table.

What is a NULL value?

A NULL value in a table is a value in a field that appears to be blank, which means a field with a NULL value is a field with no value.

The RDBMS database uses tables to store data. A table is a collection of related data entries and contains rows and columns to store data. For example:

A relational database is based on the relational model of data, which organizes data into one or more tables of rows and columns, with a unique key for each row. Generally, each entity type described in a database has its own table with the rows representing instances of that type of entity and the columns representing values attributed to that instance. Since each row in a table has its own unique key, rows in a table can be linked to rows in other tables by storing the unique key of the row to which it should be linked.

High data consistency: standardized relational databases allow the storage of data without contradictions, thus contributing to the consistency of the data. Likewise, relational systems present functions with which integrity conditions are defined and controlled automatically. The transactions that compromise the consistency of the data are blocked.

Set-oriented data processing: the relational database system is based on set-oriented processing that subdivides each entity into minimum values. This allows you to connect different entities through the content, as well as perform complex queries such as JOIN.