Dynamic SQL and Embedded SQL

What is SQL ?

Structured Query Language, or SQL, is essentially a language that databases employ. This language demonstrates how to query these tables and other related objects utilising the information handled by tables (views, functions, procedures, etc.). The majority of databases, including SQL Server, Oracle, PostgreSQL, MySQL, and MariaDB, use this language to manage data (along with various extensions and modifications).

Structured Query Language is known as SQL. It is utilised in relational database management systems to store and manage data (RDMS).

It is a common language used with relational databases. The user may make, read, update, and remove relational databases and tables with this tool. The standard database language for every RDBMS, including MySQL, Informix, Oracle, MS Access, and SQL Server, is SQL. Users can query the database using a variety of SQL queries that resemble English in many respects.

RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems such as IBM DB2, MS SQL Server , MySQL , Oracle, and Microsoft Access. The data in a RDBMS is stored in the database objects known as tables. A table is the collection of the related data entries, and it contains columns and rows. SQL stands for structured query language which is used to manipulate database objects and data they contain. It is comprised of several different statements which are used in manipulation of the data. SQL being a nonprocedural is not a general-purpose language. SQL lets you access and manipulate the databases. SQL queries can be of two types that is embedded or static SQL and dynamic SQL. So, in this blog, we are going to learn about these two types of SQL statements in detail.

Example of SQL Statement :

UPDATE EMP SET NAME= ‘ABC’ WHERE ID=0007;

How is SQL Statement Processed?

Before proceeding next, it is necessary to understand how the Structured Query Language statements are processed. DBMS performs the following steps shown in the diagram:

Dynamic SQL :

The dynamic SQL programming approach allows you to create SQL statements dynamically during runtime. Because the full details of the SQL query may not be known at compilation, dynamic SQL enables the creation of many adaptable applications.

In situations when static SQL does not allow the operation or you are unsure of the precise SQL statements that should be run, dynamic SQL is employed. These claims might be influenced by user input or by the program's processing efforts.

 What exactly is dynamic SQL?

The method we use to write SQL queries so that they are dynamically created alongside application actions is known as "dynamic SQL." We can manage complex industrial applications and transactions with its assistance without incurring additional costs. Dynamic SQL allows for the creation of flexible SQL queries, and when an application is executed, the names of any variables or other arguments are provided. To develop dynamic queries that can execute whenever we want, we may utilise stored procedures.

We make advantage of the exec keyword for Dynamic SQL. In contrast to dynamic SQL, which allows for query modification during each run, static SQL does not allow for query modification during execution.

Why do we need Dynamic SQL?

We need to use Dynamic SQL for the following use cases:

1.     When we need to run dynamic queries on our database, mainly DML queries.

2.    When we need to access an object which is not in existence during the compile time.

3.    Whenever we need to optimize the run time of our queries.

4.    When we need to instantiate the created logic blocks.

5.    When we need to perform operations on application fed data using invoker rights.

How to use Dynamic SQL?

We need to follow the following syntax while creating and executing a dynamic SQL cycle.

Syntax:

-- Start by declaring the Query variable and other required variables

DECLARE @SQL nvarchar(1000)

DECLARE @variable1 varchar(50)

DECLARE @variable2 varchar(50)

-- Set the values of the declared variables if required

SET @variable1 = 'A'

-- Define the query variable

SET @SQL = 'SELECT columnName1, columnName2, columnName3...

FROM tableName where columnName1 = @variable1

-- Prepare the statement to be run on the database

PREPARE Query FROM @SQL;

-- Execute the prepared Dynamic SQL statement

Execute Query; 

Static SQL :

In this article, we will look at embedded SQL. When we discuss embedded SQL, what we mean is that concise SQL queries are inserted into high-level languages to obtain meaningful results. In order to incorporate SQL queries into other high-level languages, we must first confirm that our system is equipped with a functional database connector. We may quickly establish new databases or execute SQL queries on the ones we already have in our RDBMS by using the connectors. Now let's explore the embedded SQL ideas in depth and learn more about them.

 

What exactly is embedded SQL?

The Structured Query Language (SQL) is referred to as such, as we have seen in our earlier courses. We conduct operations and transactions on the databases using this language. Industry-level applications require well interconnected systems that can access the database and deliver data to the user. The inbuilt SQL comes to our aid in these circumstances. We include SQL queries into high-level languages so that the logic portion of our study may be completed quickly.

 

Why do we need Embedded SQL?

We have the flexibility to use databases as needed thanks to embedded SQL. Several things need to be taken care of once the application we design enters production mode.

The issue of authorisation and the retrieval and feeding of data into and out of the database is one of a thousand things we need to take care of.

We can quickly utilise the database without writing any cumbersome code thanks to the embedding of queries. With embedded SQL, we are able to build APIs that quickly fetch and feed data as needed.

Conclusion

Dynamic SQL may be used to create adaptable applications, but only if your users are knowledgeable and skilled. Otherwise, you ought to use embedded or static SQL. Compared to dynamic SQL, this is more effective.

Presented by:

Mandar patil

Jyotika Nilgar

Nikhil Rane

Prathamesh Saraf