database tables

                               Table "public.mdl_user_enrolments"
    Column    |  Type  | Collation | Nullable |                     Default                     
--------------+--------+-----------+----------+-------------------------------------------------
 id           | bigint |           | not null | nextval('mdl_user_enrolments_id_seq'::regclass)
 status       | bigint |           | not null | 0
 enrolid      | bigint |           | not null | 
 userid       | bigint |           | not null | 
 timestart    | bigint |           | not null | 0
 timeend      | bigint |           | not null | 2147483647
 modifierid   | bigint |           | not null | 0
 timecreated  | bigint |           | not null | 0
 timemodified | bigint |           | not null | 0
Indexes:
    "mdl_userenro_id_pk" PRIMARY KEY, btree (id)
    "mdl_userenro_enr_ix" btree (enrolid)
    "mdl_userenro_enruse_uix" UNIQUE, btree (enrolid, userid)
    "mdl_userenro_mod_ix" btree (modifierid)
    "mdl_userenro_use_ix" btree (userid)

                                      Table "public.mdl_role"
   Column    |          Type          | Collation | Nullable |               Default                
-------------+------------------------+-----------+----------+--------------------------------------
 id          | bigint                 |           | not null | nextval('mdl_role_id_seq'::regclass)
 name        | character varying(255) |           | not null | ''::character varying
 shortname   | character varying(100) |           | not null | ''::character varying
 description | text                   |           | not null | 
 sortorder   | bigint                 |           | not null | 0
 archetype   | character varying(30)  |           | not null | ''::character varying
Indexes:
    "mdl_role_id_pk" PRIMARY KEY, btree (id)
    "mdl_role_sho_uix" UNIQUE, btree (shortname)
    "mdl_role_sor_uix" UNIQUE, btree (sortorder)

                                       Table "public.mdl_role_assignments"
    Column    |          Type          | Collation | Nullable |                     Default                      
--------------+------------------------+-----------+----------+--------------------------------------------------
 id           | bigint                 |           | not null | nextval('mdl_role_assignments_id_seq'::regclass)
 roleid       | bigint                 |           | not null | 0
 contextid    | bigint                 |           | not null | 0
 userid       | bigint                 |           | not null | 0
 timemodified | bigint                 |           | not null | 0
 modifierid   | bigint                 |           | not null | 0
 component    | character varying(100) |           | not null | ''::character varying
 itemid       | bigint                 |           | not null | 0
 sortorder    | bigint                 |           | not null | 0
Indexes:
    "mdl_roleassi_id_pk" PRIMARY KEY, btree (id)
    "mdl_roleassi_comiteuse_ix" btree (component, itemid, userid)
    "mdl_roleassi_con_ix" btree (contextid)
    "mdl_roleassi_rol_ix" btree (roleid)
    "mdl_roleassi_rolcon_ix" btree (roleid, contextid)
    "mdl_roleassi_sor_ix" btree (sortorder)
    "mdl_roleassi_use_ix" btree (userid)
    "mdl_roleassi_useconrol_ix" btree (userid, contextid, roleid)