SQL and PL/SQL – An Unmissable Comparison

This article was published as a part of the Data Science Blogathon.

Introduction

The essential element for any organization’s operation is data. Data is getting significant and gaining more traction by the day. Hence it is required to store such a large amount of data carefully. This brings up databases, and SQL and PL/SQL stand out as the most widely used relational database languages. Although it may appear that PL/SQL and SQL are closely related, there are several distinctions in how they function. PL/SQL may run an entire block of code simultaneously, while SQL only allows the single query execution. PL/SQL and SQL have different capabilities for handling errors, interacting with databases, and performing operations.

Although both are closely interwoven, the two languages have a few operational differences. Furthermore, there are differences between SQL and PL/SQL in terms of their performance, error handling, and database functionality. To help you understand how each language is used, this article will examine every difference between the two.

SQL

Source – msnoob.com

Structured Query Language (SQL) is a standard database language used to create, maintain, and retrieve relational databases.

SQL has the following advantages:

• In comparison with procedural languages, SQL has a higher level of abstraction.
• The software can be utilized by users in various database management systems where it is available.
• It is possible to easily port SQL if the underlying database management system is upgraded or changed.

PL/SQL

Source – bizlearn.jp

It is a block-structured language that can combine SQL power with procedural statements by clearing all the statements of a block to the Oracle engine simultaneously; processing speed increases, and traffic decreases. It is a database-oriented programming language with procedural capabilities that extends SQL. Developed by Oracle Corporation in the early 1990s, it enhances SQL’s capabilities.

Below are some of the advantages of PL/SQL:

• Its structure consists of blocks of code that can be nested within one another.
• A block is a unit of a task or a logical module.
• Its blocks are often reused within the info.
• Procedural language consists of conditional statements (if-else statements) and loops (FOR loops).
• PL/SQL engine processes multiple SQL statements simultaneously, reducing network traffic.
• Through the execution of a PL/SQL program, it handles errors or exceptions effectively.
• It is possible to take specific actions or display a message to the user once an associate degree exception is caught.

Differences Between SQL and PL/SQL

The differences are as follows:

1. Structural Query Language was developed to manipulate relational databases. The language is declarative and detail-oriented. In contrast, PL/SQL uses SQL as its database and is a procedural language. The language is application-oriented.
2. There are no variables in SQL, but there are variables constraints, data types, etc., in PL/SQL.
3. SQL uses DDL and DML to write queries and commands, whereas PL/SQL uses code blocks with functions, triggers, variables, control structures (for loop, while), and conditional statements (if, then, else).
4.  At a time, only one query or SQL operation can be executed. PL/SQL supports the simultaneous execution of multiple operations or entire blocks of code, reducing network traffic.
5.  Regarding PL/SQL, embedding is possible but not the opposite.
6.  SQL interacts directly with the database server.
7. Data manipulation in PL/SQL is fast, especially with large volumes.

PL/SQL Execution

Database procedures are stored to be called by applications as needed. Additionally, they can be called from another block. Procedures called by applications are compiled and loaded into the System Global Area for processing by PL/SQL and SQL.

Each program unit consists of a block consisting of declarations and statements. A block can be nested to include another block. The following keywords are used to identify them:

• DECLARE is used for variables, subprograms, and local types. To avoid clutter, the declarative part of a block ends when execution is complete.
• BEGIN contains statements that have access to declarations. This is the block’s executable part.
• The EXCEPTION function handles all exceptions raised during execution. To prevent exceptions from occurring within a subprogram, the exception-handling portion of the block is typically included near the program’s conclusion.

SQL Execution

In SQL, we have effective instructions that allow users to tell SQL what they want to be done. SQL then performs the task by compiling these instructions and navigating the database.

SQL statements must be used to carry out each action. Some terms in SQL are also reserved for carrying out a particular function. SELECT, UPDATE, and DELETE are a few examples. No further usage of them as names is permitted. (Note: Although SQL handles almost all operations, tools and apps are also available to simplify SQL’s job.)

In SQL, there are two main statement kinds:

• Statements in Data Manipulation Language (DML)
• Assertions in the Data Definition Language (DDL)

DML:

The likes of SELECT, DELETE, INSERT, and UPDATE are examples of DML statements. They are employed in database manipulation. You can add or delete rows, choose one or more tables, choose a view, alter values in existing rows, and perform other operations using DML statements.

Example:

• SELECT * FROM EMP_TABLE

• INSERT INTO EMP_TABLE

• DELETE FROM EMP_TABLE WHERE NAME=”ABC”

DDL:

Using DDL statements, you can build, modify, rename, or drop a schema object. Without removing the complete structure, you can also delete all the data included in a schema object. Using DDL statements, you can carry out several additional tasks.

Several DDL statements include CREATE, ALTER, DROP, TRUNCATE, ANALYSE, and COMMENT.

Example:

• CREATE TABLE EMP_TABLE

• DROP TABLE EMP_TABLE

• GRANT SELECT ON EMP_TABLE TO AAVC

Conclusion

Our discussion has covered SQL, and PLSQL, their differences, and how they are executed in this article. It is an extension of SQL and performs the same operations, control structures, and triggers that SQL does, but on massive amounts of data. The key takeaways of this article are as follows:

• SQL solely addresses the what of an action, whereas PL/SQL also provides the how.
• A sophisticated method for solving intricate SQL problems is PL/SQL.
•  PL/SQL excels in performance and speed, while SQL excels in data abstraction and portability.

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anushkakhatri

Passionate about solving business problems with data-driven solutions. Skilled in the field of Data Science and Big Data Engineering.
I have worked on various projects, including developing predictive models, analyzing complex data sets, and designing and implementing data architectures and pipelines.
I enjoy exploring new data science and data engineering techniques and keeping up with the latest industry trends.