Explaination of OpenERP domain filter with simple example:

Consider the following fields in XML view.

<field name="field1"/>

<field name="field2"/>

<field name="field3"/>

Single condition:

 

Simple condition in programming:                           

if field1 = 10

In OpenERP domain filter, it will be written as:

syntax : Each tuple in the domain has three fields ->  ('field_name', 'operator', value)

field_name : a valid name of field of the object model or in the database table

operator : valid operators are =, !=, >, >=, <, <=, like, ilike, in, not in, child_of, parent_left, parent_right (openerp/osv/expression.py)

value : a valid value to compare with the values of field_name, depending on its type.

ie, domain = [('field1','=',10)] # where field1 should be a field in the model and 10 will be the value

or domain = [('field1','=',field2)] # where field1 and field2 should be the fields in the model

Condition AND

Simple condition in programming:    

if field1 = 5 and field2 = 10

In OpenERP domain filter, it will be written as:

ie, domain = [('field1','=',5),('field2','=',10)]

or domain = [('field1','=',field3),('field1','=',field3)]

Note : Note that if you don't specify any condition at the beginning and condition will be applied.

Condition OR

Simple condition in programming:    

if field1 = 5 or field2 = 10

In OpenERP domain filter, it will be written as:

ie, domain = ['|', ('field1','=',5),('field2','=',10)]

or domain = ['|', ('field1','=',field3),('field1','=',field3)]

 

Multiple Condition

Simple condition in programming:  

if field1 = 5 or (field2 ! = 10 and field3 = 12)

In OpenERP domain filter, it will be written as:

domain = ['|',('field1','=',5),('&',('field2','!=',10),('field3','=','12'))]

Also this post from Vivek will be helpful to all. Cheers!!