Jul 15, 2011 · Storing EAV as one big table with three columns entity_id, attribute_id, value is an inefficient implementation of EAV. For more efficiency: attributes should be columns . Create new columns or tables when new attributes are introduced.

Dec 2, 2023 · I realized that EAV model can be transformed into a standard SQL table "on the fly" by creating derived table. In the derived table I use "brute force" join solution where every attribute from EAV is loaded into separate table column by separate LEFT JOIN. Here is an example using WITH for derived table definition.

Aug 13, 2012 · An EAV (aka Key-Question-Answer) table is technically in 3NF: 1NF. Rows are order-independent - True, the rows can be stored in any order. Columns are order-independent - True, the column ordering has no effect on the state of the contained data, and columns can be referenced independently of any other.

Apr 16, 2016 · In an EAV design, attributes of a relation (aka fields, or columns, of a database table) are taken out of a relation and stored as records in an Attributes tables. The values are stored in yet another table that has foreign keys to the Attributes table and an Entity table.

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EAV's power is that new data can be added with no change to structure. This means that if you want a new configuration value, you just add it to the table and pull it out where you want it in code, and you don't need to add a new field to the domain, schema, mapping, DAL queries, etc.

May 12, 2014 · The advantage compared to EAV design is that data retrieval and storage logic is a bit simpler, while maintaining small data footprint. Disadvantage is the potential cost of maintaining multiple small tables and increased number of joins.

Jul 16, 2014 · Sure, the EAV is far from ideal but now you've got some horrendous obscure table names that you the developer didn't add, with the wrong type of index (if any), with no constraints added in the code where there need to be and so on. You've given schema modification privileges to the user running the application.

My very last choice would be an EAV table as they are slow and difficult to query. If I really really needed that functionality because in fact many client defined things were not only possible but likely, I would consider using a nosql database for that part of the application. At least nosql are optimized to better use EAV structures.

When designing relational database schema for web applications, I often find a case where I end up creating a table just to contain one row, and only one row. It feels like that is the wrong way to