Enterprise Developer supports two segment layout types: 
               	 
               
 
                  		 
                  		  
                  - Default 
                     		  
                  
- You can define one default segment layout for each IMS segment; however it is not mandatory. A default segment layout formats
                     data that does not meet the conditions specified by any conditional segment layouts you have created for that segment type.
                     
                     		  
                  
- Conditional 
                     		  
                  
- You can define one or more conditional segment layouts for each IMS segment. When you create a conditional segment layout,
                     you define a test that applies to one or more fields. To use a conditional segment layout, the data in a segment occurrence
                     must satisfy all the tests defined for that layout. 
                     		  
                  
  
            	 
            Note:  
               		
                
                  		  
                  - When you initialize a segment occurrence you can choose to specify a segment layout for entering data. 
                     		  
                  
- When you modify data, the IMS Database Editor works out automatically which layouts to use for which occurrences.