I am currently building a small crm application. I need each user to be able to define their own custom fields. I am currently building this crm using php and mysql.
Example: I have a "customer" table which has the standard fields: name, phone, address, email, etc. But i want to allow the user (unique session) to add fields that are custom to his/her business which are only accessible to him (not other users). I then want these custom fields to function just like all the other fields in the table (ability to search, send and received data). I am hoping i can accomplish this in mysql and php but am open to any technology or solution that is considered best practice. Thank you for your help.
This can be done by creating a table called "customfields" with the elements "id, fieldname, company_id", then another table that would associate those custom fields with data, eg "customercustomdata: id, customfields_id, customer_id". Associate "ownership" of a field the same way
To create a new custom field, "insert into customfields (fieldname,company_id) values ('Birthday',companyid);"
Does that help?
@Matt H: Is this method considered AEV or just standard relational db?
So because i will have many users in many dif industries that will want to add their own custom fields to a number of different tables (contacts, transactions, events, etc) i am assuming that i would need the customfield table to have a user_fk/id or company fk/id, a related table fk/id, an id, and a field name? Am i on the right track? Then in the need to create a 2nd table to hold the data for each custom field buy having a customfield fk/id, customer fk/id, id and a data field to hold the actual data. Is this correct?
Ok so once i build those two additional tables how do I add them to the contacts table so it looks like one big table for the user, instead of the 3 tables?
Thanks again for you help.
Answer
after much research i have found that most people who wish to accomplish this are using document databases not relational databases.
You could place an extra column for storing string data and store an array describing the contents for custom cells. For example:
$custom = array(
array("field" => "bikesOwned", "value" => 4),
array("field" => "travelled", "value" => 14)
);
then use something like PHPs json_encode to store that data in the extra cell. Then all you would need to do is decode and process the array.
Some people suggesting using the Entity-Attribute-Value design, but before you do, please read Bad CaRMa, a story about an EAV-like design that nearly destroyed a company because it was unmaintainable.
To solve this better, read How FriendFeed uses MySQL to store schema-less data. You can lump all the custom columns into a single BLOB, and store it that way. Then if you want individual attributes to be searchable, create a table for that attribute, that maps values back to the customers table.