What is PL/SQL?

Bluebird

December 29, 2021

Where there is Oracle, there is a need for PL/SQL as well. What does PL / SQL mean? Learn more from the blog post!

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A relational database management system stores the vast majority of company data. In many cases, a relational database management system is a synonym of Oracle products.

However, where there is Oracle, there is a need for PL/SQL as well.

Introduction to the SQL Programming Language

The exponential growth of unstructured data is one of the most spectacular outcomes of the digitalizing world and the breakthrough of multimedia content. Big Data supported the generation of a number of new fields of technology, and data science has a promising future. Many would think that in parallel, traditional relational data management systems and related technologies would slowly disappear.

They couldn’t be more wrong. The relational database management (RDBMS) system still stores the vast majority of data in the world. Their standard data management language is SQL. SQL is quite versatile: with its help we can flexibly manage data stored in the datastore, query, modify, or expand them. Its extent however only reaches the datastore. As it is not a “real” programming language because it lacks control elements that could control data traffic from the datastore to the “outside world”. Hence, it is impossible to code applications with it.

A Programming Language Extended by Oracle: PL/SQL

One option is to add SQL commands among the commands of a higher-level, more general programming language (such as C), according to which the datastore manager accomplishes the tasks in the background. The other solution is to expand SQL itself with procedural elements, thus allowing application coding. Oracle, the uncrowned king of the RDBMS chose this path when they created their own SQL based programming language, the PL/SQL. (PL is short for Procedural language itself). The language admittedly inherited its syntax from Ada but elements from C++ were added as well. Its first version appeared in 1992 as part of Oracle 6.0. The fresh version of the procedural language with extended functionality has been part of every new edition of the database ever since.

Contents

PL/SQL doesn’t contain the entire SQL set of commands, only those that play a bigger role during data management processes. (for instance, commands for data definition and security are missing). In exchange, It includes basic control elements such as the WHILE cycle or the IF branching. It can create personal memory variables to store intermediate calculation results. Because SQL data management commands execute in blocks rather than one by one in the datastore, PL/SQL solutions can be very effective. And optimization works more efficiently when SQL commands are in these blocks together, not one by one.

Advantages

The language supports triggers, meaning, when a specific event occurs, the response to it runs automatically, composing several SQL commands and control elements. Stored processes can be applied when specific data management processes, conditions are placed in the datastores themselves. Registration in a central location allows multiple users to access the code more quickly.

The language also has the advantage of being easily integrated with Oracle's system. (SQLPlus, SQLForms, etc.) It is also useful that it is independent of the operating system; its specific structure and format only depend on the running datastore manager. Any application that uses one of Oracle's standard programming interfaces can access PL/SQL elements in the datastore. Along with Oracle, it now supports Times Ten and IBM DB2 datastore managers as well. In newer versions Large Objects (LOB), XML and HTTP cookie support, and among new data types, timestamp, interval or unichar have appeared.

The basic structural unit of the language is a block that comprises 3 main parts (Declare, process and error handling), but only the process part is mandatory. It's possible to declare local variables in the Declare section, and the error handling section specifies how to handle data management errors. The speciality of PL/SQL is that the blocks can embed themselves under one another practically infinitely.

Is Efficiency Sufficient?

As is usually the case with older programming languages, an alarm has been triggered over PL/SQL as well. However, it seems to be too soon. While its field of application and popularity doesn’t grow, it will not disappear anytime soon. Oracle's datastore manager has a solid foothold in the company's infrastructure (especially in Hungary). Consequently, PL/SQL will always have a place.

High efficiency data processing happens always near the data and in this area, PL/SQL will keep reigning. (It remains true that what PL/SQL can do, other layers can do it, with different tools and other programming languages - just not as efficiently). As a practising foreign expert said on the internet: “If something runs on an Oracle database, it doesn’t matter what other language is used by the front-end application. There is no better, more secure, a faster place for storing the logic used to manage data, than a stored procedure that was coded in PL/SQL.”

The Future of PL/SQL Programmer

The future of the language, and the PL/SQL experts seems guaranteed. There won’t be less work, because the abundance of data will create the need for newer and newer applications. Since there are fewer PL/SQL developers, existing developers will have more opportunities (and can expect a higher salary). Even if a company changes from Oracle and SQL to another technology or another data management approach (NoSQL for example), there will still be a need for an expert knowing SQL who can make such a migration.

PL/SQL Courses

In Hungary, most continuative training facilities offer PL/SQL courses where you can learn the basics of the language in five days. Knowing the basic functions of databases and knowing another language can make learning easier. It doesn’t hurt to know how to code in Java and/or Python as well, anyway.

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