How can I split keywords from a comma-separated string in a MySQL table and create efficient relationships for post querying?

Splitting Keywords for Posts Using PHP and MySQL

In this context, we will efficiently split keywords stored in a single column of a table and distribute them among two new tables, ensuring data integrity and optimized querying.

Background:
We have a table named 'post_tags' containing post IDs (post_id) and corresponding tags (tags_csv) separated by commas. Our goal is to create two additional tables: 'keywords' to store unique keywords and 'post_keywords' to associate keywords with posts.

Optimized Solution:
We can utilize MySQL's stored procedure to accomplish this task efficiently. The 'normalise_post_tags' procedure meticulously iterates through the post tags, extracting keywords, and inserting them into the 'keywords' table. It then associates keywords with post IDs in the 'post_keywords' table.

Implementation Details:

1. Data Preparation:

   • Create the 'post_tags' table with post IDs and tags.
   • Create the 'keywords' table with a unique key for keyword names.
   • Create the 'post_keywords' table with a composite primary key of keyword_id and post_id.

2. Stored Procedure:

   • The 'normalise_post_tags' procedure uses a cursor to iterate through the 'post_tags' table.
   • It identifies keywords by splitting the 'tags_csv' string at commas, trimming the keywords, and inserting them into 'keywords' if they do not exist.
   • The procedure obtains the keyword_id for each keyword (or retrieves the ID if the keyword already exists) and stores the association in the 'post_keywords' table.

3. Execution:

   • Execute the 'normalise_post_tags' procedure to perform the splitting and insertion.

Advantages of This Approach:

• Efficiency: By using a stored procedure, we eliminate repeated connection and execution overhead, which significantly improves performance.
• Data Integrity: The composite primary key in the 'post_keywords' table ensures that keyword and post associations are unique.
• Optimized Querying: The clustered composite primary key in 'post_keywords' allows for efficient queries on keyword-post relationships.

Example Usage:

After populating the 'post_tags' table with data, executing the 'normalise_post_tags' procedure will create the 'keywords' and 'post_keywords' tables, splitting and associating keywords with posts in an optimized manner.

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