我正在做一个web应用程序，我需要为一些主要的更改做一个分支，事情是，这些更改需要更改数据库模式，所以我想把整个数据库放在git下。
我怎么做呢?是否有一个特定的文件夹，我可以保存在git存储库下?我怎么知道是哪个?我如何确定我放入了正确的文件夹?
我需要确定，因为这些更改是不向后兼容的;我可不能搞砸。
在我的例子中，数据库是PostgreSQL
编辑:
有人建议进行备份并将备份文件置于版本控制之下，而不是将数据库置于版本控制之下。说实话，我觉得这真的很难接受。
肯定有更好的办法。
更新:
好吧，没有更好的方法了，但我还是不太相信，所以我要稍微改变一下问题:
我想将整个数据库置于版本控制之下，我可以使用什么数据库引擎来将实际数据库置于版本控制之下，而不是转储?
sqlite是git友好的吗?
因为这只是开发环境，所以我可以选择任何我想要的数据库。
Edit2:
我真正想要的不是跟踪我的开发历史，而是能够从我的“新的根本性变化”分支切换到“当前稳定的分支”，并且能够用当前稳定的分支修复一些错误/问题等。这样，当我切换分支时，数据库就会自动地与我当前所在的分支兼容。 我不太关心实际数据。
当前回答
在git版本控制下存储每个级别的数据库更改就像每次提交时推送整个数据库，每次拉取时恢复整个数据库。 如果您的数据库很容易发生重大更改，并且您无法承担丢失它们的代价，那么您可以更新pre_commit和post_merge钩子。 我对我的一个项目也做了同样的事情，你可以在这里找到方向。
其他回答
我遇到过这个问题，因为我有一个类似的问题，其中一些近似于基于DB的目录结构，存储“文件”，我需要git来管理它。它是分布式的，在云上使用复制，因此它的接入点将通过MySQL。
上述答案的要点，似乎类似地提出了一个问题的替代解决方案，使用Git来管理数据库中的一些东西，这有点错过了重点，所以我将尝试回答这个问题。
Git是一个系统，它在本质上存储了一个增量(差异)数据库，可以对其进行重新组装，以重现上下文。git的正常使用假设上下文是一个文件系统，而那些增量是该文件系统中的diff，但实际上所有git都是一个增量的分层数据库(分层，因为在大多数情况下，每个增量都是一个至少有一个父级的提交，以树状排列)。
理论上，只要你能生成一个增量，git就可以存储它。问题是git通常期望它生成delta的上下文是一个文件系统，类似地，当您签出git层次结构中的一个点时，它期望生成一个文件系统。
If you want to manage change, in a database, you have 2 discrete problems, and I would address them separately (if I were you). The first is schema, the second is data (although in your question, you state data isn't something you're concerned about). A problem I had in the past, was a Dev and Prod database, where Dev could take incremental changes to the schema, and those changes had to be documented in CVS, and propogated to live, along with additions to one of several 'static' tables. We did that by having a 3rd database, called Cruise, which contained only the static data. At any point the schema from Dev and Cruise could be compared, and we had a script to take the diff of those 2 files and produce an SQL file containing ALTER statements, to apply it. Similarly any new data, could be distilled to an SQL file containing INSERT commands. As long as fields and tables are only added, and never deleted, the process could automate generating the SQL statements to apply the delta.
The mechanism by which git generates deltas is diff and the mechanism by which it combines 1 or more deltas with a file, is called merge. If you can come up with a method for diffing and merging from a different context, git should work, but as has been discussed you may prefer a tool that does that for you. My first thought towards solving that is this https://git-scm.com/book/en/v2/Customizing-Git-Git-Configuration#External-Merge-and-Diff-Tools which details how to replace git's internal diff and merge tool. I'll update this answer, as I come up with a better solution to the problem, but in my case I expect to only have to manage data changes, in-so-far-as a DB based filestore may change, so my solution may not be exactly what you need.
使用像LiquiBase这样的工具，可以让你保持对LiquiBase文件的修订控制。您可以仅为生产标记更改，并让lb为生产或开发(或任何您想要的方案)使您的DB保持最新。
采用一个数据库转储，并对其进行版本控制。这样它就是一个平面文本文件。
我个人建议同时保留一个数据转储和一个模式转储。通过使用diff，可以相当容易地看到从一个修订到另一个修订的模式中发生了哪些变化。
如果您正在进行大的更改，那么您应该有一个用于进行新模式更改的辅助数据库，而不会触及旧数据库，因为正如您所说的，您正在进行一个分支。
我们曾经在一个标准的LAMP配置上运行一个社交网站。我们有一个活动服务器、测试服务器和开发服务器，以及本地开发人员机器。所有这些都使用GIT进行管理。
On each machine, we had the PHP files, but also the MySQL service, and a folder with Images that users would upload. The Live server grew to have some 100K (!) recurrent users, the dump was about 2GB (!), the Image folder was some 50GB (!). By the time that I left, our server was reaching the limit of its CPU, Ram, and most of all, the concurrent net connection limits (We even compiled our own version of network card driver to max out the server 'lol'). We could not (nor should you assume with your website) put 2GB of data and 50GB of images in GIT.
To manage all this under GIT easily, we would ignore the binary folders (the folders containing the Images) by inserting these folder paths into .gitignore. We also had a folder called SQL outside the Apache documentroot path. In that SQL folder, we would put our SQL files from the developers in incremental numberings (001.florianm.sql, 001.johns.sql, 002.florianm.sql, etc). These SQL files were managed by GIT as well. The first sql file would indeed contain a large set of DB schema. We don't add user-data in GIT (eg the records of the users table, or the comments table), but data like configs or topology or other site specific data, was maintained in the sql files (and hence by GIT). Mostly its the developers (who know the code best) that determine what and what is not maintained by GIT with regards to SQL schema and data.
When it got to a release, the administrator logs in onto the dev server, merges the live branch with all developers and needed branches on the dev machine to an update branch, and pushed it to the test server. On the test server, he checks if the updating process for the Live server is still valid, and in quick succession, points all traffic in Apache to a placeholder site, creates a DB dump, points the working directory from 'live' to 'update', executes all new sql files into mysql, and repoints the traffic back to the correct site. When all stakeholders agreed after reviewing the test server, the Administrator did the same thing from Test server to Live server. Afterwards, he merges the live branch on the production server, to the master branch accross all servers, and rebased all live branches. The developers were responsible themselves to rebase their branches, but they generally know what they are doing.
如果测试服务器上有问题，例如。合并有太多冲突，然后代码被恢复(将工作分支指向'live')， SQL文件永远不会执行。在执行sql文件时，这被认为是一个不可逆的操作。如果SQL文件不能正常工作，则使用Dump恢复DB(开发人员被告知，因为提供了测试不佳的SQL文件)。
今天，我们同时维护一个sql-up和sql-down文件夹，它们具有相同的文件名，开发人员必须测试这两个正在升级的sql文件是否可以同样降级。这最终可以用bash脚本来执行，但是如果有人一直监视升级过程，这是个好主意。
虽然不是很好，但还是可以控制的。希望这能让你深入了解一个真实的、实用的、相对高可用性的站点。也许它有点过时，但仍然被遵循。
我在我的个人项目中做的是，我把我的整个数据库存储到dropbox，然后点MAMP, WAMP工作流，从那里使用它。这样，数据库总是最新的，无论我需要做一些开发。但这只是针对开发!现场是使用自己的服务器，当然!：）
