How to Retrieve an Oracle Sequence Value Without Incrementing It?

Retrieving Sequence Value Without Incrementing

A common task in database management is fetching the current value of a sequence without altering its sequence. While it may seem like a simple operation, it requires a specific SQL instruction to prevent the sequence from being incremented.

The Oracle database provides a solution through the following SQL:

SELECT last_number
FROM all_sequences
WHERE sequence_owner = '<sequence owner>'
AND sequence_name = '<sequence_name>';

This query retrieves the current value stored in the last_number attribute. It queries the all_sequences data dictionary view, which maintains metadata about sequences in the database. By specifying the sequence_owner and sequence_name, you can target the specific sequence whose value you wish to obtain.

Using the above SQL, you can effectively retrieve the sequence value without triggering its increment. This is particularly useful when you need to check the sequence value for diagnostic purposes or when you want to preserve its value for potential future use.

Other views that provide sequence metadata include user_sequences and dba_sequences. These views are also accessible to extract information about sequences in different schemas and databases.

Additional Considerations:

• If the sequence is in your default schema, you can simplify the query using user_sequences:

SELECT last_number
FROM user_sequences
WHERE sequence_name = '<sequence_name>';

• If you want to retrieve all sequence metadata, you can utilize * to select all attributes.
• In case your sequence is configured with a cache size greater than 1, you can manually decrement and increment the sequence to retrieve its value without affecting the true sequence value. However, this operation should be performed with caution to avoid potential conflicts with other users accessing the sequence concurrently.

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