database infrastructure development

We are a field service business with a strong inventory function based in Australia. We are looking to build a primarily mobile based (IPAD) database management system. This will be a task based, field service management system, this system will include: - Workorder tracking with invoice calculation and conversion functionality; - Sign on glass (POD) on wok orders; - Asset management with specific fields and associated inventory components; - Inventory and warehouse function; - Allow for geofencing of regions and user allocations; - User and time stamping on customers notes; and - An appointment and booking function; The system will need to be able to integrate with Salesforce (CRM related fields, customer purchase history and activity notes) aswell as Xero for all invoice and purchasing fields We have workorders with multiple tasks – each task is allocated to asset and each asset is made up of a standard or predefine template of component inventory items (We call them Kits) which is allocated to that asset. Consumption of component inventory items is not a 1 or 0 proposition (i.e. it could be a some, all or none of the component items that are replaced). Predefined templates are not customer specific and can be used across customers, in additions a customer may use multiple predefined templates for different assets on their site. Predefined templates may include common component inventory items. Where a workorder consists of multiple tasks with multiple assets – all with different predefined templates – we will need the invoice to consolidate common assets onto a single line. The service component of the workorder is time based and based on a standard rate per hour- the time aspect will start calculating based on when (1) workorder is opened and (2) when the customer signs on glass. This job was posted from a mobile device, so please pardon any typos or any missing details.