Oracle Skills

Oracle is a widely used relational database management system that provides a powerful query language for retrieving data. In some cases, retrieving the names of columns in a specific table may be useful. This article will show you how to fetch colu…

In Oracle SQL, constraints enforce rules on data stored in a table. Constraints can be used to enforce data integrity, such as ensuring that a column always contains a specific type of data or that a column always has a value. If you want to see the…

When designing a database, you'll have to make one important decision: whether or not to use foreign keys. A foreign key is a constraint that enforces a relationship between two tables. For example, you might have a table that contains informati…

Oracle SQL Developer is a powerful and popular tool for working with Oracle databases. One useful feature of Oracle SQL Developer is the ability to use variables in SQL statements. Variables allow you to store values that can be used in multiple sta…

Oracle is a powerful and widely-used database management system. By default, Oracle listens for incoming connections on port 8080. However, there may be situations where you need to change the Oracle port from 8080 to a different value. This can be …

Tableau is a powerful data visualization tool that allows you to connect and analyze data from various sources. However, it has a limit of 40 columns that can be displayed in a single view. If you have more than 40 columns, it can be challenging to …

In PL/SQL, you can use the SQL%ROWCOUNT attribute to determine the number of rows affected by an UPDATE statement. SQL%ROWCOUNT is a built-in attribute that returns the number of rows affected by the last executed SQL statement. Here is an example o…

In Oracle, you can use the "V$SESSION" and "V$PROCESS" views to list the active or open connections in the database. The "V$SESSION" view contains information about all active sessions in the database, while the "V…

In Oracle, the "(+)" operator is used in a SQL query to indicate a "left outer join" or "left join" between two tables. The basic syntax of the query is as follows: SELECT column1, column2, ... FROM table1, table2 WHERE…

You can use the "ROWNUM" keyword in Oracle to select the top "n" records from a query result. The basic syntax of the query is as follows: SELECT column1, column2, ... FROM table_name WHERE ROWNUM <= n; Where: "column1, c…

In Oracle, you can use the "ALTER TABLE ... ADD CONSTRAINT" statement to add an "ON DELETE CASCADE" constraint to a foreign key. The basic syntax of the statement is as follows: ALTER TABLE child_table ADD CONSTRAINT fk_name FORE…

In Oracle, you can use the "DBA_CONSTRAINTS" view to find a specific constraint on a table. The "DBA_CONSTRAINTS" view contains information about all constraints in the database, including their name, type, and the table they are…

In Oracle, the string concatenation operator is the "||" (two vertical bars) symbol. The operator is used to concatenate or join two or more strings together. For example, to concatenate the strings 'Hello' and 'World' toge…

In Oracle, you can retrieve the current value of a sequence without incrementing it by using the "CURRVAL" pseudocolumn. The syntax of the query would be: SELECT sequence_name.CURRVAL FROM DUAL; Where "sequence_name" is the name …

You can reset a sequence in Oracle to a specific value using the "ALTER SEQUENCE" statement. The basic syntax of the statement is: ALTER SEQUENCE sequence_name RESTART WITH new_value; Where "sequence_name" is the name of the sequ…

In the Oracle database, you can turn off password expiration for a specific user by altering the user's profile and setting the "password_life_time" attribute to "UNLIMITED." You can do this by using the following SQL command…

The ORA-12505 error occurs when a client tries to connect to an Oracle database using a SID (system identifier) that the listener is unaware of. This can happen for several reasons: The SID specified in the connect descriptor does not match any of t…

Python is a popular programming language used for data analysis and data science. Tableau is a powerful data visualization tool that enables users to analyze and understand their data in a visually appealing way. Exporting data from Python to Tablea…

In Oracle, you can use the GROUP_CONCAT() function and the GROUP BY clause to concatenate column values from multiple rows into a single string. The GROUP_CONCAT() function is not a built-in function in Oracle, but you can use the following ways to …

In Oracle, you can use the GROUP BY clause with the MAX() function to group the result set by one or more columns and return the maximum value of a date column for each group. For example, if you have a table called "ORDERS" with columns &…

In Oracle, you can get the column names of a table using the "ALL_TAB_COLUMNS" data dictionary view. The "ALL_TAB_COLUMNS" view contains one row for each column of each table, view, or materialized view in the database that is ac…

There are several resources available for database performance tuning, including: Oracle documentation: Oracle provides a wealth of documentation on performance tuning, including best practices, tutorials, and case studies. This can be found on the…

Embedding Tableau visualizations into a web page can enhance the user experience and provide a more interactive and dynamic way to display data. The Tableau JavaScript API allows you to embed Tableau content into a web page and provides a way to int…

Pandas is a popular Python library for data analysis and manipulation. It provides a robust data structure called a data frame, which can be used to represent and manipulate data in a tabular format. Tableau, on the other hand, is a powerful data vi…

Yes, in Tableau, it is possible to hide or unhide a column of data within a worksheet, similar to Excel. This can be useful when you want to temporarily remove a column from your visualization or focus on a specific set of columns. This article will…

Data labels in Tableau Desktop can be added to a box plot to provide more context and detail about the data. This article will explore how to add data labels to a box plot in Tableau Desktop. Create a Box Plot: To add data labels to a box plot, crea…

The error message "ODI-1227: ActiveMQObjectMessage cannot be cast to javax.jms.BytesMessage" often occurs when working with Java Message Service (JMS) applications. This error indicates that an attempt was made to cast an ActiveMQObjectMes…