I am a newbie and try to read about SharePoint and I read enterprise keyword and managed metadata but I don't know what's the difference between them is there a relation ? when I need to use it , How ?
Enterprise keyword is a word or phrase that is added to items on a SharePoint site.
It's a good way to capture some of the knowledge of the people who use the content. To make it easy for users to add keywords, you can add a special enterprise keywords column to a list or library. Then, to add a keyword to an item, users just select the item and enter the word or phrase they want in the item properties.
Regarding is there a relation ?
A Managed Metadata column is a special kind of column that you can add to lists or libraries. It enables site users to select terms from a specific term set. A Managed Metadata column can map to an existing term set, or you can create a local term set specifically for the column.
The enterprise Keywords column is a column that you can add to content types, lists, or libraries to enable users to tag items with words or phrases that they choose. By default, it is a multi-value column. When users type a word or phrase into the column, SharePoint presents type-ahead suggestions. Type-ahead suggestions might include items from managed term sets and the Keywords term set. Users can select an existing value, or enter something new.
Also , Managed Metadata is the data type of Enterprise keyword.
For more details check Introduction to managed metadata
Regarding How to use it ?
You can add
Enterprise keywords column in your list or library as the following :
Go to List Setting > click on Enterprise Metadata and Keywords Settings.
Click the check box next to Add an Enterprise Keywords column to this list and enable Keyword synchronization. Click OK
Now the Enterprise Keywords column should be added to our default view
For more details check
Managed Metadata as a field type is bound to a specific taxonomy hierarchy. Ie, "Location" or "Product". All of those hierarchies wind up in the termstore in different Term Sets. There is also a grab-bag termset in the term store called "Keywords". These are terms that have no real "meaning". They don't have relationships or hierarchies, they don't have translations, etc. All we have is a name.
The Enterprise Keywords field allows the user to pick any public term from the termstore - both managed terms in termsets, as well as terms from the keywords. If the keyword that a user enters isn't in the termstore, it will add it to the keywords termset. if it appears multiple times, the user will be asked to disambiguate ("Turkey the location, or Turkey the bird")