Pl Sql Stored Procedures Pdf To Word

A stored procedure is a set of SQL statements that can be executed on the database. It is stored as a object in the database. A stored procedure allows for code that is run many times to be saved on the database and run at a later time, making it easier for yourself and other developers in the future. Functions can be used in any SQL command. However, stored procedures cannot be used in this way.

There are several different databases that implement stored procedures, and each of them implement it in their own way. These are offered in languages that extend the functionality of the standard SQL language. The alternative to using stored procedures is to have the code you need to run stored in your application, or in SQL scripts.

Pl sql stored procedures pdf to word

This means the application user will need read and write access to the tables, knowledge on how to insert the data in the correct way, as well as extra security to protect from SQL injection.

If you use a stored procedure, you can include your SQL code inside the procedure, and then let applications access the stored procedure. There is also less risk of SQL injection as being inside a stored procedure can handle that you can write your own SQL injection-proof code. Stored procedures mean that the code required to manipulate the database is stored in a database object, and not inside the application.

This means that it can be developed separately, which is a big advantage of object-oriented programming, and is useful when working with teams as one developer can work on the application code and another can work on the stored procedure.

Create a Stored Procedure

It can also be easier to maintain. If you know that there is an issue with the data from the database, you can likely isolate it to the stored procedure. Because all of the code exists in the stored procedure inside the database, it can be easier for the developer or database administrator to tune or improve the performance. Stored procedures can have their code analysed using database-specific tools, logs can be analysed, and execution plans created to see how code is run.

This is easier to do in the database in a stored procedure than inside application code. If a query is stored in the application code, the query is sent to the server. The server then looks up the results, and sends the results back to the application for further processing.

This could be hundreds or thousands of records. Using a stored procedure means the code to call the stored procedure is sent from the application to the database.

The database runs the stored procedure, processes the results, and sends those results back to the application. All of the processing is done on the database, and the final and hopefully smaller result set is sent to the application.

This often means less network traffic, and ultimately a faster process. Databases can store data for many different applications. Often they are designed for just a single application, but many applications can connect to them. For example, the logic to calculate the payment due date of an order, or the number of business days between two dates.

This means that any application that uses this database can use these stored procedures and get the same results. It also means the code is reusable.

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Other applications can use this same code and not have to write it themselves. The code is easier to maintain as it is in a single place, not spread out over multiple applications. Starting a debugging session or process for application code can be easy.

I think the biggest disadvantage to stored procedures is being able to include it in version control systems. Application code can be easily included in your version control system as it would sit inside your project.

However, with a stored procedure, the definition is on the database. To store a version of the stored procedure, you would need to use a. You would need to remember to keep that file up to date.

PL/SQL - Procedures

Another disadvantage of using stored procedures is that it is harder to move the business logic between databases. If you want to move your database from one vendor e. This differs slightly between each database vendor. By default, MySQL treats the default delimiter, the semicolon ; as an end of statement command. When this character is found, the statement ends.

So, if we write a stored procedure, and it includes a semicolon, MySQL sees that as the end of the stored procedure. This is a simple example of a stored procedure.

Table of Contents

It will look up data in an employee table and return the results. There are a range of best practices or recommendations that I can suggest here. There is no need to add the object type as a prefix to the name of the object.

It makes it harder for any future changes, because if you decide to use a synonym , then the name of the synonym indicates it is not a synonym. It also reduces the amount of characters you can use.

In Oracle, the limit is around 30 characters, so taking up 3 or 4 characters with a prefix is not ideal. Using table aliases is also easier to write, as you can just enter the alias each time you want to specify a column. Many IDEs will trigger the auto-complete once you do this, making writing the query even easier.

Stored Procedures

When using functions or expressions in your queries, the output from those can be messy. The column headings are just a concatenation of the columns and functions used.

PL/SQL tutorial 42: How To Create PL/SQL Stored Procedure With Parameters In Oracle Database

The first shows the e. This makes it clearer because of the reasons above. SQL is not a case sensitive language. This is the case for programming in general, but you should be able to tell what the variable represents by looking at its name.

Adding spaces to your code improves the readability.

Oracle PL/SQL Stored Procedure & Functions with Examples

This is both for spaces in between words, and line breaks. I put spaces after and sometimes before symbols in my SQL queries. I add spaces after commas when specifying groups and orders. It might not seem like much, but adding spaces in your code in a consistent manner, and where it makes sense, will improve the readability of it, and help other developers. It will still run, as long as the code that calls the procedure will specify the values in the same order.

SQL Stored Procedures: The Complete Guide

You have the ability to specifu output parameters in stored procedures. These are parameters that return a value back to the calling code.

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This makes it easier to see that this parameter is an output parameter. Many IDEs have a code formatting feature, allowing you to press a button and automatically format the code. Many of these IDEs even allow you to configure how the formatting is done for example, the commas in the SELECT statement could go at the start or the end of each line.

I recommend formatting your stored procedure code. Like everything else in this section, it makes it easier to maintain and easier to read. You can read his article for more information, but in short, creating packages to house your stored procedures is a good idea as it means:. Stored procedures are a great feature of a database.

They have many advantages and handle much more than standard SQL code. What has your experience with stored procedures been? Is it all new to you, or have you written some before? Do you have any questions on stored procedures? Let me know in the comments below.

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Made for Oracle developers

Ben Brumm DatabaseStar. Three pages of SQL commands - print it or use it as a quick reference. Your privacy is protected. Do you want to know what a stored procedure is, how it can help your SQL, and how to create one? Read this guide to find out all of those, and more.

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