One to many relationship php

PHP handle array when query database with one-to-many relationship - Code Review Stack Exchange

one to many relationship php

The solution is to create a new table which will act as the 'many' in two 'one-to- many' relationships, with each of the original tables acting as the. You are probably going to have to take the data and make the array that you want . $data = array(); foreach ($result as $item) { $key = $item['name']; // or. Display data from two tables - one to many relationship.

Why not c, cg, pn or similar? That could leave you with a query like: Outside of format, your query seems odd in that it doesn't seem to match the relations you have noted. You said the relationships are: You are taking a very standard approach to populating a multi-dimensional array from a results set that represents one-to-many relationships.

one to many relationship php

As noted above, you could have null values for the contract group information and the phone number information. You don't seem to be considering this at all.

How to handle a Many-to-Many relationship with PHP and MySQL

This modified form will still show which occurrence of table 'A' has been selected, but it will then list all occurrences of table 'B'. Against each occurrence of table 'B' will be a checkbox to indicate if an associated occurrence exists on table 'X' or not. The user will be able to toggle the checkbox in order to create or delete the entry on table 'X'.

one to many relationship php

The MySQL query to select the data is as follows: END statement checks the existence of an associated occurrence on 'X' and sets a column named 'selected' to 'T' if one exists or 'F' if one does not. As an added refinement I use a third form to allow the entry of selection criteria so that the contents of the second form can be refined.

  • How to handle a Many-to-Many relationship with PHP and MySQL

This is usually more relevant in those cases where there are more columns to be displayed, but it does provide the ability to select only those occurrences of 'B' where associated occurrences of 'X' either do or do not exist. For this I have a standard procedure which has as its input two arrays: In that case, you may define a "morph map" to instruct Eloquent to use a custom name for each model instead of the class name: Querying Relations Since all types of Eloquent relationships are defined via methods, you may call those methods to obtain an instance of the relationship without actually executing the relationship queries.

In addition, all types of Eloquent relationships also serve as query buildersallowing you to continue to chain constraints onto the relationship query before finally executing the SQL against your database. For example, imagine a blog system in which a User model has many associated Post models: Dynamic Properties If you do not need to add additional constraints to an Eloquent relationship query, you may access the relationship as if it were a property.

For example, continuing to use our User and Post example models, we may access all of a user's posts like so: Because of this, developers often use eager loading to pre-load relationships they know will be accessed after loading the model. Eager loading provides a significant reduction in SQL queries that must be executed to load a model's relations.

Querying Relationship Existence When accessing the records for a model, you may wish to limit your results based on the existence of a relationship.

Eloquent: Relationships

For example, imagine you want to retrieve all blog posts that have at least one comment. To do so, you may pass the name of the relationship to the has and orHas methods: For example, you may retrieve all posts that have at least one comment and vote: These methods allow you to add customized constraints to a relationship constraint, such as checking the content of a comment: For example, imagine you want to retrieve all blog posts that don't have any comments.

one to many relationship php

To do so, you may pass the name of the relationship to the doesntHave and orDoesntHave methods: These methods allows you to add customized constraints to a relationship constraint, such as checking the content of a comment: For example, the following query will retrieve all posts with comments from authors that are not banned: This means the relationship data is not actually loaded until you first access the property.

However, Eloquent can "eager load" relationships at the time you query the parent model.

displaying php mysql query result with one to many relationship - Stack Overflow

So, if we have 25 books, this loop would run 26 queries: Thankfully, we can use eager loading to reduce this operation to just 2 queries. When querying, you may specify which relationships should be eager loaded using the with method: Eager Loading Multiple Relationships Sometimes you may need to eager load several different relationships in a single operation. To do so, just pass additional arguments to the with method: For example, let's eager load all of the book's authors and all of the author's personal contacts in one Eloquent statement: For this reason, Eloquent allows you to specify which columns of the relationship you would like to retrieve: Constraining Eager Loads Sometimes you may wish to eager load a relationship, but also specify additional query constraints for the eager loading query.

Of course, you may call other query builder methods to further customize the eager loading operation: For example, this may be useful if you need to dynamically decide whether to load related models: The array values should be Closure instances which receive the query instance: For example, perhaps you need to insert a new Comment for a Post model. Instead, we called the comments method to obtain an instance of the relationship.

Display data from two tables - one to many relationship

If you need to save multiple related models, you may use the saveMany method: Again, the difference between save and create is that save accepts a full Eloquent model instance while create accepts a plain PHP array: You may use the createMany method to create multiple related models: Belongs To Relationships When updating a belongsTo relationship, you may use the associate method. This method will set the foreign key on the child model: This method will set the relationship's foreign key to null: This pattern is often referred to as the Null Object pattern and can help remove conditional checks in your code.

For example, let's imagine a user can have many roles and a role can have many users.

one to many relationship php