rows Archives - You Should Know

Tips to Prevent Duplicate Rows in Oracle

March 3, 2026 by admin

Oracle is a relational database management system (RDBMS) that stores data in tables. Each table has a primary key, which is a unique identifier for each row in the table. When you insert data into a table, Oracle checks to see if a row with the same primary key already exists. If it does, Oracle will not insert the new row, and you will get an error message.

There are a few reasons why you might want to avoid duplicate rows in your Oracle database. First, duplicate rows can waste space. Second, they can make it difficult to query your data. Third, they can lead to data integrity problems.

The Ultimate SQL Guide: Master the Art of Avoiding Duplicate Rows

April 29, 2025 by admin

In SQL, duplicate rows can occur when data is inserted without checking for existing duplicate values. This can lead to data integrity issues and make it difficult to work with the data. There are a few different ways to avoid duplicate rows in SQL, including using the UNIQUE constraint, the PRIMARY KEY constraint, or the ON DUPLICATE KEY UPDATE clause.

The UNIQUE constraint creates a unique index on a column or set of columns, which prevents duplicate values from being inserted. The PRIMARY KEY constraint creates a unique index on a column or set of columns and also identifies the row as the primary key of the table. The ON DUPLICATE KEY UPDATE clause allows you to specify an action to be taken when a duplicate value is inserted, such as updating the existing row.