67

Summer '15 is going to include the GA release of Custom Metadata Types. See Introducing custom metadata types: the app configuration engine for Force.com

Are Custom Metadata Types intended as a complete replacement for Custom Settings?

I gather from the article linked above that the big advantage to Custom Metadata Types is that a baseline collection of metadata records can also be deployed in packages.

Are there other advantages? Such as support for lookup relationships or protected values that can only be accessed my code within the managed package? Is there such a thing as hierarchy custom metadata types?

Are there advantages to using Custom Metadata Types with respect to limits? In particular SOQL limits?

See also: How to use custom metadata types to save years of development on app configurations

  • 3
    I think the custom settings will still stay and the main purpose will be the hierarchy access. The custom metadata types will replace the list custom settings. You mentioned the biggest advantage, you can deploy them and package them. In regards to SOQL, it won't count towards the limits as it's cached metadata. – Boris Bachovski May 3 '15 at 23:50
  • 5
    @Daniel - I agree that this feature (at least for now) appears to be a bit of a head-scratcher. If instead we just had the ability to deploy data as part of a package, including Custom Setting and Custom Object rows, that would appear to do almost everything that this new feature offers. I have to wonder whether is some future roadmap around custom metadata that makes it more meaningful than just basically ListCustomSettings++. I also think that "Apex Tests see all records without SeeAllData" could cause problems for config-dependent tests. – jkraybill May 4 '15 at 1:01
  • 1
    Here's another article that sheds some light on it: developer.salesforce.com/blogs/engineering/2015/05/…. Biggest thing looks like you can protect some settings. I think I saw that lookup relationships are coming to custom metadata types. Right now there is no custom UI for entering or updating records - that's a huge hole. – Daniel Hoechst May 4 '15 at 4:22
  • 1
    @DanielHoechst - Layoutable UI for entering and updating records is one of the big features coming out in Winter -- take a look at developer.salesforce.com/blogs/engineering/2015/08/… . – Avrom Roy-Faderman Aug 13 '15 at 23:47
  • 1
    @DanielBallinger - record-level protection of configuration (as opposed to hiding the entire type, which is both a custom settings and a Summer CMT feature) is another. (The third big feature is field-level control over who can edit values. By setting a field to subscriber editable, you'll be able to default the value in a package and let customers change that value if they need to. – Avrom Roy-Faderman Aug 13 '15 at 23:50
62

I’m the original inventor of and lead developer for custom metadata types.

Although we have a variety of use cases in mind, custom metadata types are primarily intended to let you develop peers of Salesforce standard metadata types, such as custom fields, tabs, or workflow rules (obviously in this first release we don’t have the power required to duplicate all the functionality in these types).

Just as you can’t perform CUD on such types in Apex today (you can’t create a new tab, modify a custom field, or delete a workflow rule in Apex), you can’t yet perform CUD on custom metadata types in Apex, short of a metadata API callout. You can help us get that feature prioritized by voting for the idea here. To see how to create tooling using Apex for a custom metadata type, you can look at Jean-Baptiste Pringuey’s sample “configurator.”

Testing is a tricky question, which I address in a blog post I just posted. The use case you describe is definitely a legitimate one. There's been a fair bit of demand for configuration visibility to ftests. See the idea Custom Settings should be treated as a Setup Object for APEX Tests

There’s a lot more planned for custom metadata types than custom settings on steroids. App configurations that don’t have to be re-created in every environment and that can respect managed state (so you can have some that are not deletable or mutable by subscribers) was just a starting place that filled a known need. Aaron’s second blog post gives you a taste of things to come in the near term (safe harbor applies, of course).


Winter `16 features

Layoutable UI for entering and updating records is one of the big features that came out in Winter -- take a look at Custom metadata types: they’re money; actually, even better!

Record-level protection of configuration (as opposed to hiding the entire type, which is both a custom settings and a Summer CMT feature) is another.

The third big feature is field-level control over who can edit values. By setting a field to subscriber editable, you'll be able to default the value in a package and let customers change that value if they need to.


More recent features

It's been a while!

Custom Metadata types now support (as of Summer 17):

  • Picklist fields
  • Relationships to records of other custom metadata types, to SObject types (EntityDefinition), and to SObject fields (FieldDefinition)
  • Text Area (Long) fields
  • Asynchronous (but not requiring remote site settings) upsert in Apex via Metadata.MetadataOperations.enqueueDeployment()
  • Validation formulas (including traversal of relationships)
  • It sounds like there are lots of good things coming to close the gap with the existing list custom settings and provide. I've voted for the linked ideas. – Daniel Ballinger May 5 '15 at 0:21
  • Any plans to include RICH TEXT or even a LOOKUP as a field type in custom metadata? That would be useful help for us. Here is the idea to vote up. please sfdcfanboy.wordpress.com/2016/01/12/… – sfdcFanBoy Apr 13 '16 at 4:32
  • We're considering rich text. We're definitely planning (in fact actively working) to support relationships, though their behavior will be a little different from a regular lookup field. – Avrom Roy-Faderman Apr 13 '16 at 7:03
21

I came up with the below advantages (and disadvantage). I'd be interested if you see any other ones.

  • Perhaps the biggest advantage Custom Metadata Types have over Custom Settings is that the data themselves are considered to be Metadata. So, essentially, you have Metadata about Metadata. Technically, they are called “Components”, and the reason this is important, is because you can DEPLOY the records!
  • Since the Records themselves are Metadata, they are refreshed to Sandboxes; even those with no data.
  • Since the Records themselves are Metadata, APEX Tests can see them even with “SeeAllData=False”. No more creating Custom Settings for Test Classes! • Custom Metadata
  • Types are more like a custom object than Custom Settings. This means it takes a little more time to create them, but you have more control such as page layouts and other features.
  • Starting with Winter ’16, like a custom object might have, you can Track Audit Trail history! This is a must have feature!
  • Like Custom Settings, Custom Metadata Types do not cost a SOQL when referencing them. Moreover, you can reference a Custom Metadata Type with a standard SOQL instead of using the special Custom Settings Class. For example: Select ID, Field1__c, Field2__c, … From My_CustomMetadataType__mdt
  • Like Custom Settings, all records are Cached. So you don’t need to worry about performance, and indeed, this will provide better performance over a normal table.

Disadvantage:

  • Unfortunately, at this time, if you want to create a MAP of all of the values for a given Custom Metadata Type, you must query all records and then populate it through a loop, similar to how you would for a normal table. Unlike Custom Settings which have a getAll method to create a MAP for you.
  • Though this is a record (has an ID), it can't be linked to from another object via a Lookup.
  • 1
    Found my own answer for the 1st Disadvantage which turns out to be false. You can get all of the entries with: Set<String> mdtNames = CustomMetadata.SFDC_Health_Check__mdt.getAllNames(); Map<String, CustomMetadata.SFDC_Health_Check__mdt> cmdMap = CustomMetadata.SFDC_Health_Check__mdt.getByNames(mdtNames); – Bob Nunemaker Sep 23 '15 at 14:22
  • I tried your approach @Bob, it is not working for me. Set<String> mdtNames = CustomMetadata.SFDC_Health_Check__mdt.getAllNames(); Map<String, CustomMetadata.SFDC_Health_Check__mdt> cmdMap = CustomMetadata.SFDC_Health_Check__mdt.getByNames(mdtNames); It says Method does not exist or incorrect signature. Even I have defined SFDC_Health_Check__mdt Custom Metadata Types. – user31154 May 1 '16 at 10:41
  • 1
    Yeah, that was for the Beta version and they left it out in the delivered version. Silly to do so. But you can just create your own MAP method in your program and load it there. And if you want, a Utility method where you pass the name of the CMD, and then it does it with dynamic APEX and passes back a MAP<string, sObject>. – Bob Nunemaker May 7 '16 at 3:25
8

I've done quite a bit of research on Custom Metadata Types vs Custom Settings, and I've found that in only a few cases are Custom Settings more useful. Custom Metadata types have a number of advantages that make them the correct choice to implement almost always. A lot of this has already been said, but some things have been added recently, so I thought I'd add my two cents.

Advantages to Custom Metadata:

  • Most importantly, as stated before, they are Metadata and thus deployable! No more annoying configuration after deployment, which you have to do with Custom Settings. They're also refreshed to sandboxes, so you don't need to create Apex classes to generate your default Custom Setting records.
  • They have WAY more options that Custom Settings: picklist fields, long text areas (in Spring '17), page layouts, and validation rules (though as of Winter '17 these are not deployable either by change set or by migration tool - weird!)
  • The beauty that is Metadata Relationships! You can create lookups between Custom Metadata objects. Additionally, you can create an Object Definition lookup - so you're relating Custom Metadata to Standard or Custom Object definitions. Additionally, in Spring '17 you can create a dependent lookup to a Field Definition on that object. (Documentation here)
  • Custom Settings have the same permission to edit the records and to edit the configuration. Both can be done with the "Configure Application" permission. With Custom Metadata, you can edit the records with "Configure Application" but you require "Author Apex" to edit the configuration.
  • Custom Metadata types have a lot of additional features specific to developing managed packages. You can configure the visibility and editability of fields an objects both by the org that installs the package and by upgrades to the package.

Reason why you would use custom settings instead:

  • Hierarchies - Custom metadata types do not purport to replace hierarchy custom settings which allow you to vary values based on users and profiles across the org. These custom settings can also be referenced in formulas, so can be used in formula fields, validation rules, workflow rules, and visualforce. (Documentation here)
  • Web service credentials - If you’re using test credentials in a sandbox, you don’t have any reason to deploy them to production. More importantly, if you create a sandbox, you don’t want the config for the production versions of your Web Services being created automatically and used by default. However, it is usually best to use Named Credentials for this.
  • Custom setting records’ values can be edited in code, while custom metadata cannot. If you will need to modify your configuration programmatically for any reason (say you’re creating a config console for the user), custom metadata will not work.

There's also been some discussion about testing here. I have a different approach which I detail in my answer to Unit Test - Creating Custom Metadata.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.