RDBMS Interview Questions

In SQL, normalization of data is a process through with data is organized in tables used for the reduction of redundancy and dependency of data. It divides large tables into smaller ones using some set of rules.

Types of normalization:

• 1NF: The rules of 1NF are that each table must contain a single value and records are required to be unique.
• 2NF: The rules of 2NF are that the table must be in 1NF and must possess a single-column primary key.
• 3NF: The rules of 3NF are that the table must be in 2NF and must not have any transitive functional dependencies.
• BCNF: The rules of the Boyce Codd Normal form is that it must be in 3 NF and must not have more than one candidate key.

Following is a list of the differences between NoSQL and RDBMS: –

• In terms of data format, NoSQL does not follow any order for its data format. Whereas, RDBMS is more organized and structured when it comes to the format of its data.
• When it comes to scalability, NoSQL is more very good and more scalable. Whereas, RDBMS is average and less scalable than NoSQL.
• For querying of data, NoSQL is limited in terms of querying because there is no join clause present in NoSQL. Whereas, querying can be used in RDBMS as it uses the structured query language.
• The difference in the storage mechanism of NoSQL and RDBMS is that, NoSQL uses key value pair, documents, column storage, etc. for storage. Whereas, RDBMS uses various tables for storing data and relationships.

The RDBMS is the Acronym of a relational database management system. This is displays the data in the form of a table. The RDBMS is allowed to create, edit, delete data in the database. The SQL Server, MySQL, Oracle, Sybase, etc are relational database management systems.

The E-R Diagram is an entity-relational diagram which is a graphically represented entity and their relationship with each other.

It is used to design a diagram of the relational database. It shows the workflow of the data process.

Some best features in RDBMS

• The data store in the form of a table.
• The multiple users allow the RDBMS.
• ACID is the Acronym of an Atomicity, Consistency, Isolation, Durability.
• Unique identification using the primary key.
• The one Column used in two or more tables.
• Normalization
• Distributed database

The RDBMS is an acronym of the (Relational Database Management System).

The RDBMS is maintained, control, create, and update data easily. It is easy for users to the developer. It is data security and better integrity. The multiple users access the RDBMS. It provides a good backup data procedure. The data can show different users differently.

The DCL means Data Control Language and DML means Data Manipulation Language commands in RDBMS. The DCL worked to control the data, rights, and permission of the database. The DML is worked for the update, create, delete the data in the database table.

The ACID means Atomicity, Consistency, Isolation, and Durability. Atomicity means to execute all the process as a single unit or not process at all. Before and after the transaction, the database must be consistent. Several transactions worked without interference and transactions are independent. The system goes fail then also operation happens successfully.

List of relational database

• SQL Server,
• Oracle Database,
• Sybase,
• Informix,
• MySQL,

• Internal level: physical storage structure of data into a database and can be to access the path.
• External level: shows the part of the database to users.
• Logical level: Structure and limitation of the database.

The RDBMS can create multiple tables in the database. It can connect in various ways. The one-to-one, many-to-many, one-to-many relation can create connections into more than two tables.

The non-relational database is not used to store data into table form. This is store data into the traditional form. NoSQL is a non-relational database.

The non-relational database has four categories:

1. Column stores
2. Document stores
3. Graph stores
4. Key-value stores.