Disclosure: I build Schemity, a desktop ERD tool - this post is from our blog and uses it for the examples.
TL;DR: Consultants juggling client engagements in one shared cloud account cannot guarantee NDA isolation or true deletion. Schemity keeps each client in a local workspace - a folder of JSON files - so isolation is physical and offboarding is a folder handover.
When several clients' schemas live side by side in one shared cloud diagram account, NDA isolation is a promise you cannot actually keep, and deletion at the end of an engagement is an act of faith in a vendor. Keeping one local workspace folder per client fixes both.
A consultant's Tuesday: in the morning you are in a fintech client's ledger schema, after lunch you are restructuring a logistics company's shipment tables, and at five someone from last year's engagement emails asking for "that diagram you made". Three clients, three NDAs, three completely unrelated data models.
And in most diagram tools: one account, one big list, everything side by side.
