CollectionId (hibernate-core JavaDocs)

```
@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface CollectionId
```
Describe an identifier column for a bag (ie an idbag). EXPERIMENTAL: the structure of this annotation might slightly change (generator() mix strategy and generator

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  java.lang.String generator
  The generator name.
  
  Type type
  id type, type.type() must be set.
- Optional Element Summary
  
  Optional Elements
  Modifier and Type Optional Element Description
  
  Column column
  
  Column[] columns
  Deprecated.
  Only basic (single column) collection-ids are supported.

- Element Detail
  - type
```
Type type
```
    id type, type.type() must be set.
- - generator
```
java.lang.String generator
```
    The generator name. For example 'identity' or a defined generator name
- - columns
```
@Deprecated
Column[] columns
```
    Deprecated.
    Only basic (single column) collection-ids are supported. Use column() instead
    
    Collection id column(s).
    
    Default:
    
    {}
- - column
```
Column column
```
    Default:
    
    @javax.persistence.Column