Oracle 23c Enhanced Querying: Eliminating the “FROM DUAL” Clause

 Introduction

In the world of database querying, Oracle has long been recognized as a powerhouse. It offers a wide range of features and capabilities that make it a preferred choice for many organizations. However, one aspect that has often set Oracle apart from other databases is the requirement to use the “FROM DUAL” clause when executing certain types of queries. In a recent update, Oracle 23c has introduced a new feature that eliminates the need for this clause, making queries more intuitive and aligning Oracle with other popular databases. In this blog post, we will explore this enhancement and its impact on Oracle users.

Understanding the “FROM DUAL” Clause

In Oracle, the “FROM DUAL” clause is typically used in queries when a table reference is required but no actual table is needed. It serves as a placeholder, providing a syntactically correct structure for the query. For example:

SELECT SYSDATE FROM DUAL;

Here, the “FROM DUAL” clause is used to select the current system date without referencing any table. While this approach has worked well in Oracle, it has often been a source of confusion for users who are more familiar with other databases that don’t require such explicit syntax.

Oracle’s Streamlined Approach

To align with industry standards and enhance the user experience, Oracle has introduced a feature that removes the need for the “FROM DUAL” clause in certain scenarios. With this update, users can now directly execute queries without referencing the DUAL table, making the syntax more intuitive and similar to other databases.

For instance, the above query can now be simplified as follows

SELECT SYSDATE;

By eliminating the “FROM DUAL” clause, Oracle simplifies the query structure and reduces potential confusion, especially for those transitioning from other database platforms.

Benefits of the Enhanced Approach

1. Improved Readability: Removing the “FROM DUAL” clause leads to cleaner and more concise queries. Developers can focus on the relevant components of their queries without the need for an unnecessary placeholder.
2. Easier Migration: As organizations adopt multi-database strategies or migrate from one database to another, developers and database administrators will find it easier to transition from other database platforms to Oracle. The elimination of the “FROM DUAL” clause simplifies the learning curve and reduces the need for rewriting queries during the migration process.
3. Consistency across Platforms: The enhanced approach brings Oracle in line with other popular databases, promoting consistency and reducing confusion for developers working across multiple platforms. It enables developers to leverage their knowledge of common querying practices without requiring significant adjustments when working with Oracle.
4. Enhanced Developer Productivity: The streamlined syntax saves developers time and effort, allowing them to focus on more critical aspects of their work. The reduction in query complexity also reduces the chances of errors or typos, leading to improved productivity and efficiency.

Conclusion

Oracle’s decision to eliminate the “FROM DUAL” clause in certain scenarios is a welcome enhancement for developers and users. By aligning with the syntax used in other databases, Oracle has taken a significant step towards making its querying process more intuitive and user-friendly. The streamlined approach not only simplifies query construction but also facilitates easier migration and fosters consistency across database platforms. As a result, Oracle users can now enjoy a more seamless experience, enhancing their productivity and overall satisfaction with the database system.

Exploring the Benefits of the Boolean Data Type in Oracle Database 23c

 In the ever-evolving world of database management systems, Oracle has consistently strived to introduce new features and enhancements to improve data handling and querying capabilities. One of the latest additions is the boolean data type introduced in Oracle Database 23c. This powerful data type brings several benefits to developers and database administrators, enhancing how boolean values are handled within the Oracle database. In this blog post, we will delve into the key features and advantages of the boolean data type.

The boolean data type in Oracle Database 23c is designed to represent two distinct states, true and false. It offers a more intuitive and expressive way of storing and manipulating logical values within the database. Unlike previous versions of Oracle, which forced users to rely on number (e.g., 0 for false and 1 for true) or character data types (e.g., ‘Y’ and ’N’) to represent boolean values, Oracle Database 23c provides a dedicated boolean data type, simplifying data modeling and improving query readability..

Example:

Create table person
( pid number,
  married boolean) ;

insert into person values(1,true );
insert into person values(2,false);
insert into person values(3,'Y');
insert into person values(4,0);

Oracle Database 23c accepts specific numbers and literals that can be converted to true or false values when working with boolean columns. Here are the accepted values for true and false:

Numbers:

• The value 0 will be converted to FALSE.
• Any other number (e.g., 1, -3, 2.657) will be converted to TRUE.

Strings (case insensitive):

• The strings ‘true’, ‘yes’, ‘on’, ‘1’, ‘t’, and ‘y’ will be converted to TRUE.
• The strings ‘false’, ‘no’, ‘off’, ‘0’, ‘f’, and ’n’ will be converted to FALSE.

Oracle Database 23c introduces a new syntax to simplify boolean expressions. The following syntax is available:

• “IS [NOT] TRUE”: This syntax allows you to check if a boolean value is true. For example, you can write “column_name IS TRUE” to check if the value of the column is true.
• “IS [NOT] FALSE”: This syntax allows you to check if a boolean value is false. For example, you can write “column_name IS FALSE” to check if the value of the column is false.

These new syntax options provide more clarity and readability when working with boolean values. They can be combined with the AND and OR operators to create complex boolean expressions.

Simplified Conditional Expressions

Boolean data types also simplify conditional expressions. Developers can write cleaner and more readable code by directly using boolean variables or columns in conditional statements. This enhances code maintainability and makes it easier to understand the logic behind complex business rules.

For example, instead of writing

select * from person where married = true;

you can simplify the statement to

select * from person where married

Also, you can include boolean expression in case statements.

select 
case when married then 'Married'
else 'Not Married'
end
from person;

Integration with PL/SQL

The boolean data type seamlessly integrates with Oracle’s procedural language, PL/SQL. PL/SQL developers can take advantage of boolean variables and parameters to improve code clarity and simplify logical operations within stored procedures, functions, and triggers. Boolean data types enable more efficient decision-making and control flow structures in PL/SQL programs.

Eg.

declare
status boolean;
begin
    status := true;
    insert into person values (5,status);
…
end;
/

Migration Assistance with to_boolean Function

To facilitate the migration of existing applications to the boolean data type, Oracle introduced the to_boolean function. This function allows developers to convert numeric or string values to their corresponding boolean representations. For example, you can use the to_boolean function to convert values like 0, ‘true’, and ‘no’ to their boolean equivalents. This simplifies the migration process and ensures data consistency.

Enhanced Data Integrity

By introducing the boolean data type, Oracle Database 23c ensures better data integrity within the database. It allows developers to enforce logical constraints more efficiently, ensuring that only valid boolean values are stored. With boolean columns, the database can enforce constraints such as CHECK constraints, ensuring that only true or false values are allowed, reducing the risk of inconsistent or incorrect data.

Improved Query Performance

The boolean data type in Oracle Database 23c also contributes to enhanced query performance. With dedicated boolean columns you can index this column and querying operations can be optimized, resulting in faster execution times for boolean-based conditions.

Conclusion

The introduction of the boolean data type in Oracle Database 23c has brought significant benefits. From improved data integrity and query performance to simplified conditional expressions and seamless integration with PL/SQL and analytical functions. The boolean data type empowers developers and database administrators to handle logical values more effectively. As Oracle continues to innovate, this enhancement showcases its commitment to providing powerful enhancements for efficient data management and processing.