In what situations should values like position_main and position_second be stored in a separate table in PHP?

Values like position_main and position_second should be stored in a separate table when there is a one-to-many relationship between the main entity and its positions. This allows for better organization of data, easier querying, and avoids redundancy in the main table. By creating a separate table for positions, you can easily retrieve, update, and delete positions associated with the main entity without affecting the main entity's data. 

// Create a separate table for positions
CREATE TABLE positions (
    id INT AUTO_INCREMENT PRIMARY KEY,
    main_entity_id INT,
    position_name VARCHAR(50),
    position_value INT,
    FOREIGN KEY (main_entity_id) REFERENCES main_entity(id)
);

// Insert positions for a main entity
INSERT INTO positions (main_entity_id, position_name, position_value) VALUES (1, 'position_main', 100);
INSERT INTO positions (main_entity_id, position_name, position_value) VALUES (1, 'position_second', 200);

// Retrieve positions for a main entity
SELECT * FROM positions WHERE main_entity_id = 1;

// Update a position for a main entity
UPDATE positions SET position_value = 150 WHERE main_entity_id = 1 AND position_name = 'position_main';

// Delete positions for a main entity
DELETE FROM positions WHERE main_entity_id = 1;

Keywords

database normalization relational database foreign key constraint data integrity SQL JOIN

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