Entity Framework- Creating Index and ForeignKey name (Oracle) -

i have problem creating automatically names constraints , indexes. after length of constraint or index exceeds 30 characters name changed f.e:

"fk_ot_personal_equi_1685080621" 

fortunately saw in method there parameter used name specific constraints , indexes.

        createtable(             "otdba.ot_personal_equipment",             c => new                 {                     equipment_id = c.decimal(nullable: false, precision: 10, scale: 0),                     active_time = c.decimal(nullable: false, precision: 19, scale: 0),                     show_mode = c.decimal(nullable: false, precision: 10, scale: 0),                     resource_id = c.decimal(nullable: false, precision: 10, scale: 0),                 })             .primarykey(t => t.equipment_id)             .foreignkey("otdba.ot_resources",  t => t.resource_id, cascadedelete: true,name: "fk_ot_equipment_resources")             .index(t => t.resource_id); 

unfortunately doesn't work , if check auto-generated script have:

alter table "otdba"."ot_personal_equipment" add constraint "fk_ot_personal_equi_1685080621" foreign key ("resource_id") references "otdba"."ot_resources" ("resource_id") on delete cascade 

/

without including change fk_ot_equipment_resources

basic question. why?