SQL Interview Questions And Answers

SQL Interview Questions And Answers

SQL Interview Questions And Answers:

Learn More About PLSQL


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SQL Interview Questions And Answers

You’ve probably heard of SQL and once you understand this programming language, you might be tempted to stick with it. However, do you know what PLSQL is? What advantages and benefits can you take if you learn PLSQL? Find out by reading this informative blog post! sql interview questions

Overview of  SQL:
PL/SQL is a procedural language introduced during the late 1970s and early 1980s. It was originally known as PL/S and had some features that made it non-interoperable with other SQL implementations. These problems were fixed in Oracle9i ( sql interview questions ) and SQL:2008.
This article will cover all the basics of PLSQL, its language structure, some of the most common interview questions you may encounter, and some more advanced tips. PLSQL is an SQL-like programming language developed by IBM.

What is SQL?
The PL/SQL programming language was developed by Oracle Corporation in the late 1980s as a procedural extension language for SQL and the Oracle relational database.
PL/SQL is a block-structured language that enables developers to combine the power of SQL with procedural statements. All the statements of a block are passed to the oracle engine all at once which increases processing speed and decreases the traffic. sql interview questions PL/SQL extends SQL by adding constructs found in procedural languages, resulting in a structural language that is more powerful than SQL. The basic unit in PL/SQL is a block. All PL/SQL programs are made up of blocks, which can be nested within each other.

Reasons to choose SQL?
It’s a relational programming language used in the Oracle 10g to 12c database. Plsql is quite popular because building applications in an Oracle Database is so easy with it sql interview questions. There are several reasons why you may want to learn PLSQL.
Even if you’re not specifically looking to expand your programming knowledge, it gives you the opportunity to improve your overall skills and save money. Learning PLSQL will also save time because PLSQL is an efficient way of handling queries without having to write multiple queries for various routine computational tasks.

Features of SQL [sql interview questions] :

PL/SQL is basically a procedural language, which provides the functionality of decision making, iteration, and many more features of procedural programming languages.
PL/SQL can execute a number of queries in one block using a single command.
One can create a PL/SQL unit such as procedures, functions, packages, triggers, and types, which are stored in the database for reuse by applications.
PL/SQL provides a feature to handle the exception which occurs in PL/SQL block known as the exception handling block. Applications written in PL/SQL are portable to computer hardware or operating system where Oracle is operational. sql interview questions
PL/SQL offers extensive error checking.

Advantages of SQL:
sql interview questions 

Tight Integration with SQL.
High Performance & High Productivity.
Portability & Scalability.
Manageability.
Support for Object-Oriented Programming.
Support for Developing Web Applications.

Tips for learning SQL:
If you ensure about your PLSQL skills and how to approach a job interview, this blog is for you. It gives you tips on how to prepare for an interview and what questions to expect. One of the main things it talks about is “know your core competencies” which are all the skills that make you comfortable with programming in general.
When learning PLSQL, you’ll need to know some basic SQL commands. The most common ones are SELECT, INSERT, UPDATE, DELETE. You’ll also need to know about the data types in SQL. For example, integers are for numbers on a range of 0-9 with no decimal places.

What is the basic structure of SQL?
PL/SQL program units organize the code into blocks. The anonymous block has three basic sections that are declaration, execution, and exception handling. Only the execution section is mandatory and the others are optional. The declaration section allows you to define data types, structures, and variables.

What is the trigger in SQL with examples?
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Triggers are stored programs, which are automatically executed or fired when some events occur. Triggers are, in fact, written to be executed in response to any of the following events like database manipulation (DML) statement (DELETE, INSERT, or UPDATE) A database definition (DDL) statement (CREATE, ALTER, or DROP).

Why is SQL needed?
PL/SQL gives high productivity to programmers as it can query, transform, and update data in a database. PL/SQL saves time on design and debugging by strong features, such as exception handling, encapsulation, data hiding, and object-oriented data types. Applications written in PL/SQL are fully portable.

What are the different types of SQL Units?
Following are some different types of PL/SQL units:

Anonymous Block.
Function.
Library.
Procedure.
Package Body.
Package Specification.
Trigger.

What are functions in SQL?
A stored function (also called a user function or user-defined function) is a set of PL/SQL statements you can call by name. Stored functions are very similar to procedures, except that a function returns a value to the environment in which it is called. User functions can be used as part of a SQL expression.

SQL Execution Environment:
The PLSQL engine resides in the Oracle engine. The Oracle engine can process not only a single SQL statement but also a block of many statements. The call to the Oracle engine needs to be made only once to execute any number of SQL statements if these SQL statements are bundled inside a PLSQL block.

What are Data Types in?
• Numeric: Numeric values on which arithmetic operations are performed.
• Character: Alphanumeric values that represent single characters or strings of characters.
• Boolean: Logical values on which logical operations are performed.
• Datetime: Declares Dates and times.

Control Structures in SQL?
PL/SQL has three categories of control statements: conditional selection statements, loop statements and sequential control statements.

Conclusion:

SQL stored procedures are compiled once and stored in executable form, so procedure calls are efficient. Because stored procedures execute in the database server, a single call over the network can start a large job. This division of work reduces network traffic and improves response times.

Frequently Asked Questions:
How do you code in SQL?
What is the package in SQL?
What are the components of the SQL package?
What are identifiers in SQL?

Here you will find answers to questions on everything from the features you can expect, all of which makes up part of the SQL training from Intheairwebreathe.

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