[SVN] what is SVN? How do you use it?

SVN What is it? ？

SVN Is an open source version control system .

SVN subversion

Store data that changes over time .

The data is placed in the central resource management repository （Repoitory） in — Similar to a file server , Will remember every file change .

Code version management tools

It can remember every modification

View all the modification records

Restore and delete files

Simple concept

• repository Source code library
• Checkout extract
• Commit Submit
• Update to update

Development process ：Update( Get the latest code ) --> Make your own modification and debug successfully --> Commit( You can see your changes ) .

When two programmers modify the same file / On the same line ？

SVN Managing source code is done in units of behavior , That is to say, as long as two programmers don't modify the same line of programs ,SVN Both changes are automatically merged . If it's the same line ,SVN Will prompt the file Conflict, Conflict , Need to confirm manually .

SVN and Git difference ：

Easy to use , Quick start

Directory permission control , Enterprise security is a must

subdirectories CheckOut Check out the , Reduce unnecessary file checking out

CVS and SVN difference ：

CVS Computer parallel version system （Concurrent Version System）： Only single file history can be tracked

SVN Version control tools （Subversion）: Track directory changes over time , Both directories and files can be versioned .

SVN Compared with CVS advantage ：

1. Atomic submission

   Submit single or multiple files at a time , All submitted as a whole .

   If an accident happens halfway / Transmission interruption , It will not cause incomplete database and data corruption .

2. rename 、 Copy 、 Actions such as deleting files are saved in the version history .

3. For binaries , A space saving method is used .（ Simple understanding , Just save the differences from the previous version ）

4. The catalog also has a version history .

   The whole tree can be moved or copied , Easy to operate , And can keep all version records .

5. The overhead of branching is very small .

6. Optimized database access , So that some operations can be done without accessing the database .

   This reduces a lot of unnecessary network traffic with the database host .

SVN The main function of ：

1. Directory and file version control

2. Real version history

   stay Subversion in , You can add （add）、 Delete （delete）、 Copy （copy） And rename （rename）

3. Automatic submission

4. Metadata included in version control

5. Choose a different network layer

6. Consistent data processing

7. Valid branches (branch) And labels (tag)

8. Hackability

SVN Main application ：

1. Developers use it for code management
2. Used to store some important files , For example, contracts.
3. File sharing within the company , And can divide permissions by Directory

SVN Basic operation

• Submit and update

  Check out the CheckOut

  newly added Add

  Submit Commit

  to update Update

  Historical record

• Revocation and modification

  1. Undo local changes
  2. Undo what has been submitted
  3. Restore to the specified version

• Add ignore

  How to ignore files , Some documents do not want to be submitted , You can add ignore

• Resolve conflicts

  • Under what circumstances is conflict prone ？

    Several people modified the same line of two files

    Binaries that cannot be merged

  • How to avoid conflict ？

    Update and synchronize others' code frequently

    Binary files should not be operated by more than one person at the same time

  • What to do if there is a conflict ？

    Manually resolve modification conflicts , Or directly use the other party's

• Branch

  When do I need to open a branch ？

  Isolate online and development versions

  Large function development , Don't want to affect others , Independent development branch to develop

• The staging

  What's the use of temporary storage ？

  Situation 1 ： The code has changed a lot , But there is an urgent need to modify one Bug, But the code is finished , Cannot submit .

  Case 2 ： A lot of code rewriting , Suddenly need to release a new version , But the code can't run yet , Cannot submit .

  In this case, you can temporarily store the code ,

• Complex code merging

  situation ：

  Trunk development new functions , Changed a lot

  The branch is an online version , A lot of changes bug

  The code of the two branches has been different for a long time , Cannot directly branch merge or specify modification record merge

  Use BeyondCompare Tools compare and merge

SVN Directory structure ：

svn Branch

• svn Classic directory structure ：

  trunk trunk

  branches Branch

  tags label

​ Repositories Warehouse ： Store quilt svn Managed project files , You can store the source code , Documents, etc. ;

​ Users user ： Create and edit users ;

​ Groups Permission group ： Create and edit user groups ;

SVN Workflow and architecture diagram

SVN Operation mode ：

SVN Architecture diagram ：

operation SVN Two ways of server ：

1. command-line Command line mode ;

2. GUI-client Graphical interface mode ;

   • svn Service connection mode ：

     （1） internet network connections ：

     ​ apache The server ;

     ​ svn The server ;

     （2） local Local connection ：

   • svn Data storage mode ：

     ​ File mode ：FSFS（ Recommended ）

     ​ Database mode ：BerkeleyDB（ Berkeley DB）