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.

Monitoring and Viewing DRCP Settings:

Monitoring and Viewing DRCP Settings:

To ensure optimal performance and troubleshoot any potential issues related to DRCP, it's essential to monitor and view the DRCP settings in your Oracle database. The following scripts can be used to gather valuable information about the DRCP configuration and monitor its performance:

1. Viewing DRCP Configuration: To view the current DRCP configuration settings, you can execute the following SQL query:

sql
Select * from DBA_CPOOL_INFO;

This query provides details such as the maximum number of pooled servers, session pooling mode, minimum and maximum number of sessions per pooled server, and other relevant DRCP settings.

2. Monitoring DRCP Statistics: Oracle provides dynamic performance views to monitor the DRCP statistics. The following query can be used to retrieve information about the current DRCP pool and server statistics:

sql
SELECT * FROM GV$CPOOL_CC_STATS

These views offer insights into metrics such as the number of connections created, connections in use, connections released, and other statistics related to DRCP pool and server utilization.

3. Monitoring DRCP Performance: To monitor the performance of the DRCP connections and identify potential bottlenecks, you can execute the following SQL query:

sql
SELECT * FROM GV$CPOOL_CC_STATS

This query provides valuable information about the performance metrics of the DRCP connections, including the number of requests, average response time, and connection queue length.

4. Checking DRCP Status: To check the overall status of the DRCP feature in your Oracle database, you can use the following query:

sql
select a.connection_status,a.*  from gv$cpool_conn_info a; 

The returned status can be "ENABLED" if DRCP is active or "DISABLED" if it's currently disabled.

5. Monitoring DRCP Session Activity: To monitor the activity of individual DRCP sessions and connections, you can query the v$drcp_sessions view:

sql
select sess.inst_id Inst, sess.username, sess.sid,
       sess.server,
       sess.seq#, round(sess.wait_time_micro/1000000,1) time_waited, sess.event, sess.state, sess.status,
       sess.program, sess.machine, sess.module, sess.action
  from gv$session sess
where sess.server = 'POOLED'
order by sess.sid;

This view provides details about the active DRCP sessions, including the session ID, username, client identifier, and other relevant information.

By regularly running these monitoring scripts, database administrators can gain insights into the current DRCP settings, track performance metrics, identify potential issues, and take necessary actions to optimize the performance of DRCP in their Oracle database.

Conclusion:

Monitoring and viewing the DRCP settings in Oracle is crucial for ensuring optimal performance and troubleshooting any potential issues. By utilizing the provided scripts to gather information about the DRCP configuration, monitoring statistics, and tracking performance metrics, database administrators can effectively manage and optimize the DRCP feature to enhance the performance of their Oracle database-driven applications.

Connecting to Autonomous Database with Database Resident Connection Pooling (DRCP)

Connecting to Autonomous Database (ADB ) with Database Resident Connection Pooling (DRCP)

Introduction:

Oracle Autonomous Database (ADB) offers powerful features to simplify database management and optimize performance. One such feature is Database Resident Connection Pooling (DRCP), which provides efficient management of open connections. By leveraging DRCP, you can reduce database resource requirements and scale for simultaneous connections. In this blog post, we will guide you through the process of connecting to Autonomous Database using DRCP and highlight important considerations for working with DRCP.

Connecting with a Pooled DRCP Server Process:

To connect to Autonomous Database using a pooled DRCP server process, follow these steps:

Step 1: Locate the tnsnames.ora File: Locate or obtain the tnsnames.ora file that you are using to connect to your Autonomous Database. This file contains the necessary configuration details for establishing a connection.

Step 2: Modify the tnsnames.ora File: Edit the tnsnames.ora file and add the server type as SERVER=POOLED to enable DRCP for your connection. The modified entry should resemble the following example:

plaintext
example_high = (description= 
     (address=(protocol=tcps)(port=1522)(host=adb.example.oraclecloud.com))
     (connect_data=(service_name=example_high.oraclecloud.com)(SERVER=POOLED))
     (security=(ssl_server_dn_match=yes)))

Ensure that you replace "example_high" with the appropriate service name for your Autonomous Database instance.

Step 3: Download Client Credentials (Wallets): To securely connect to Autonomous Database, you need to download the client credentials (wallets). Refer to Oracle's documentation for instructions on how to obtain the client credentials (wallets) required for authentication.

Step 4: Connect to Autonomous Database: With the modified tnsnames.ora file and the downloaded client credentials (wallets), you can now establish a connection to Autonomous Database using DRCP. Depending on your programming language or framework, use the appropriate connection method and provide the necessary connection details.

Important Considerations for DRCP in Autonomous Database:

1. DRCP Enabled by Default: DRCP is enabled by default in Autonomous Database. However, using DRCP is optional. To connect using a pooled connection, specify SERVER=POOLED in the tnsnames.ora file. If you do not specify SERVER=POOLED, you will connect with a dedicated connection.

2. Connection Pooling Benefits: DRCP enables efficient sharing of server processes among multiple user processes, reducing resource requirements and enabling scalability for simultaneous connections. Leveraging connection pooling can significantly enhance the performance of your applications.

3. DRCP is recommended when there are applications the connects and disconnects after every transaction or you need to startup a application with a huge number of INACTIVE sessions.

Conclusion:

Connecting to Autonomous Database with Database Resident Connection Pooling (DRCP) provides efficient connection management and scalability for simultaneous connections. By modifying the tnsnames.ora file to include SERVER=POOLED and utilizing the client credentials (wallets), you can establish a connection to Autonomous Database using DRCP. With DRCP enabled by default in Autonomous Database, you can leverage connection pooling benefits to optimize the performance of your applications while reducing resource requirements.