Generating Random Data for SQL Tables: A Guide to Populating Your Database

Описание: Learn how to efficiently populate your SQL tables with random data using PL/SQL, ensuring that your performance optimization queries yield visible results.
---
This video is based on the question https://stackoverflow.com/q/67212041/ asked by the user 'Ciuboss' ( https://stackoverflow.com/u/11528313/ ) and on the answer https://stackoverflow.com/a/67216441/ provided by the user 'EJ Egyed' ( https://stackoverflow.com/u/7110099/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Populate tables with random data

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Generating Random Data for SQL Tables: A Guide to Populating Your Database

When tasked with optimizing SQL queries, one of the crucial steps is ensuring that your database contains a sufficient amount of data. This not only allows you to run various queries effectively but also provides a clearer picture of how different optimization methods impact performance. In this guide, we will discuss how to populate your SQL tables with random data, specifically focusing on a user’s request based on their SQL and PL/SQL requirements.

Understanding the Problem

You are working with two primary tables, trip and facturi, that will hold substantial data entries. The challenge lies in filling these tables efficiently with random data, particularly in a way that respects the foreign key relationship between them (with facturi referencing id_trip from trip). Achieving this through PL/SQL can seem daunting without prior knowledge of sequence generation or looping mechanisms.

The Structure of Your Tables

Before proceeding with the solution, let’s briefly recapitulate the structure of your tables:

Trip Table: Holds information about trips and contains fields:

id_trip: a unique identifier for each trip.

driver_mark: a numeric rating associated with the trip.

Facturi Table: Transactions or invoices related to the trips, which includes:

id_factura: a unique identifier for invoices.

price: the cost associated with the transaction.

discount: the potential discount applied to the invoice.

id_trip: a foreign key linking back to the trip table.

Now that we have an understanding of the tables, let’s dive into the solution.

Populating the Tables Using PL/SQL

To address the need for a significant number of entries in your tables, we can utilize PL/SQL to create a script that generates random data. Below are the two primary SQL insert statements to accomplish this.

Inserting into the Trip Table

The following command will populate the trip table with 1000 random entries. You can adjust the number of records by changing the LEVEL parameter:

[[See Video to Reveal this Text or Code Snippet]]

Inserting into the Facturi Table

Next, you need to populate the facturi table while ensuring that each entry corresponds to an existing id_trip from the trip table. The SQL statement below accomplishes this:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the SQL Scripts

First Statement (Trip):

ROWNUM: Automatically generates sequential numbers for id_trip.

DBMS_RANDOM.VALUE(1, 100): Generates a random driver mark between 1 and 100.

Second Statement (Facturi):

Each factura has a unique identifier generated through ROWNUM.

The price and discount fields have random values, where the discount is conditionally created based on a random check.

The LEFT JOIN operation ensures that each invoice links to a random trip, fulfilling the foreign key requirement.

Conclusion

Filling your SQL tables with random data is crucial for testing and optimization purposes. The PL/SQL scripts provided will allow you to efficiently insert thousands of records into your trip and facturi tables, ensuring that your optimization trials are conducted under realistic conditions. Use these scripts as a starting point and modify them as needed for your specific requirements.

With this knowledge, you should be equipped to generate substantial random datasets and effectively execute your assignments and optimizations. Happy querying!