![]() Install graphviz from MacPorts via your Terminal:.Sequel Pro can export Graphviz dot files, and then all you need is a few tools to create the diagram. Here again, the application layer is responsible for ensuring referential integrity, so you won't find any foreign keys.If you need a diagram of your MySQL database and you’re on a Mac, generating an ERD diagram is quite easy – and completely free. So two columns are used to indicate what the note references. This is because a note can be attached to different entities (e.g. For example, look at civicrm_note which has columns entity_id and entity_table. Some tables use "dynamic foreign keys".So in this case the payment_instrument_id column actually references the value column in civicrm_option_values (but only for records in civicrm_option_values with the appropriate option_group_id.) Here there is no foreign key, so referential integrity is managed at the application layer, not the database layer. You'll notice there's no table called civicrm_payment_instrument. For example, look at civicrm_contribution which has a column called payment_instrument_id. Lots of columns reference civicrm_option_values when they just need a simple (and user-configurable) list of options.In some places CiviCRM defines schema using a construct called pseudoconstants which produces some slightly more complex logic.So the table civicrm_activity_contact is used as the glue because it has foreign keys to both. For example, a contact can have many activity records, and an activity can have many contact records. Many-to-many relationships use "join tables" as intermediary tables.For example when you see a column called address_format_id, you can be relatively sure that it references civicrm_address_format.id Columns which reference other tables are named (usually) with the table name + _id.Every table has an id column as a primary (and thus unique) key. ![]() For the most part, the following patterns hold true: Specifically, looking at the names of the columns in each table goes a long way towards understanding the relationships between tables. While MySQL Workbench is the best tool I've found for inspecting the CiviCRM data structure, other tools (such as phpMyAdmin) offer lots of the same functionality. So we can see that each country has multiple state_provinces. Here, we get an even more comprehensive picture because, not only do we see tables referenced by civicrm_country, we see tables which reference civicrm_country. We can look at the foreign keys which are relevant to this table. For example, we can see that each country has an associated address_format. We can see that columns have comments which explain (to some extent) the meaning of the data stored in the columns.įrom the column names (and comments), we can also get some idea of the relationships between tables. We can look at the list of columns in the table. Let's look at civicrm_country (a relatively simple example) by opening the "Table inspector" for that table. The table name generally gives you a good idea of the type of data it stores. Look at the list of tables in the database. Then you inspect this local database with MySQL workbench and it will be both faster and safer than looking at the live one. You can use it to connect to a remote server like your live CiviCRM site, but for purposes of learning I'd recommend that you install MySQL locally and load a copy of your live CiviCRM database onto your local computer. It's similar to phpMyAdmin, but IMHO way better. MySQL workbench is an awesome tool that has helped me tremedously in understanding CiviCRM's schema. Other ways to learn about CiviCRM's schema Using MySQL workbench (Currently over 150, and more when you add custom fields!) At this scale, a diagram becomes a rat's nest of confusion. In my opinion, CiviCRM's schema is just too big to make any sort of diagram useful. I was eventually able to generate such a diagram with a special tool, but in the end, my attempts to learn from this diagram were a fantastic waste of time. If #3 is sufficiently unrelated to #1 and #2, I would suggest creating a separate question for it) Why an ER (Entity Relationship) diagram might not be helpfulĪs a visual learner, I too looked for an ER diagram when first trying to understand the CiviCRM database schema.
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