h2. The SchemaManager

Apache DS has to keep the schema elements available from all the parts of the server. This is done through what we call the *SchemaManager*. It hides all the internal structure from the users.

h3. Description

The *SchemaManager* stores all the Schema elements (*[AttributeTypes (e)]*, *[ObjectClasses (e)]*, ... Internally, we store those elements into the *Registries*, which are hives where each Schema Objects are stored.

From the user point of view, the *SchemaManager* is seen as a representation of the available schemas. It can of course be extended, or modified, by adding or removing some schema elements.

The server has one instance of a *SchemaManager*, which is used internally, and a user won't control it, in any case. On the client side, we can load a *SchemaManager* either from the server (and then we have a duplicated instance), or from existing schema files. We can even create a brand new *SchemaManager* and fill it with all what we need.

h3. Content

The *SchemaManager* stores all the 11 kind of schema elements :

|| Name ||
| *[ObjectClass (e)]* |
| *[AttributeType (...)]* |
| *[LdapSyntax (e)]* |
| *[MatchingRule (e)]* |
| *[DITContentRule (e)]* |
| *[DITStructureRule (e)]* |
| *[NameForm (e)]* |
| *[MatchingRuleUse (e)]* |
| _*[SyntaxChecker (e)]{*}_ |
| _*[Normalizer (e)]{*}_ |
| _*[LdapComparator (e)]{*}_ |

The last three elements are ApacheDS specific.

All those elements have some tight relationships. The following schema expose all the relations between all those elements :

!SchemaObjects.png|border=1!


h3. Using a SchemaManager