问题
On creating Installers, I came across both patch and upgrade. Whats is the major difference between a patch and and upgrade? Is a patch similar to update?
回答1:
A patch is basically a diff between two MSI databases of the same product (e.g. v1.0.0 and v1.0.1) and can be installed only on target machines where its target MSI (i.e. v1.0.0) is installed. It can be used only for updating an installed product. It cannot be installed standalone.
A major upgrade is the installation of a new product version (e.g. v2.0.0) over an old version (e.g. v1.0.0). When performed, a major upgrade firstly removes completely the old version and, then install the new version of your product. An installation package built as a major upgrade can also be installed as a standalone installation.
Check the Patch Packages and Major Upgrades Windows Installer articles for more details.
回答2:
All patches are update, but not all updates are patches.
A patch is a piece of software designed to update a computer program or its supporting data, to fix or improve it. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance. Though meant to fix problems, poorly designed patches can sometimes introduce new problems (see software regressions). (source: wikipedia)
A new feature in the system is not a patch, but it is also an update.
来源：https://stackoverflow.com/questions/26998393/difference-between-patch-and-update