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# SVN Lifecycle This chapter discusses the lifecycle of a version control system. * * * ### Create Repository A repository is like a central space where all developers' work results are stored. A repository not only stores files but also includes the history of every modification, i.e., the change history of each file. The Create operation is used to create a new repository. In most cases, this operation is performed only once. When you create a new repository, your version control system will ask you for some information to identify the repository, such as the location where it is created and the name of the repository. * * * ### Checkout The Checkout operation is used to create a working copy from the repository. A working copy is a developer's private workspace where content modifications can be made and then committed to the repository. * * * ### Update As the name implies, the Update operation is used to update the repository. This operation synchronizes the working copy with the repository. Since the repository is shared by the entire team, your working copy becomes outdated after others commit their changes. Let's assume Tom and Jerry are two developers on a project. They both check out the latest version from the repository and start working. At this point, the working copy is fully synchronized with the repository. Then, Jerry efficiently completes his work and commits the changes to the repository. Now Tom's working copy is outdated. The Update operation will pull Jerry's latest changes from the repository and update Tom's working copy. * * * ### Make Changes After checking out, you can perform many operations to make changes. Editing is the most common operation. You can edit existing files, such as adding/deleting files. You can add files/directories. However, these added files and directories do not immediately become part of the repository; they are added to the pending changes list until the Commit operation is performed, at which point they become part of the repository. Similarly, you can delete files/directories. The delete operation immediately removes the file from the working copy, but the actual deletion of the file is only added to the pending changes list until the Commit operation is performed, at which point it is truly deleted. The Rename operation can change the name of a file/directory. The "Move" operation is used to move a file/directory from one location to another within the repository. * * * ### Review Changes After you check out or update your working copy, your working copy is fully synchronized with the repository. However, after you make some modifications to your working copy, your working copy becomes newer than the repository. It is a good habit to review your changes before performing the Commit operation. The Status operation lists the changes made in the working copy. As we mentioned earlier, any changes you make to the working copy become part of the pending changes list. The Status operation is used to view this pending changes list. The Status operation only provides a list of changes but does not provide detailed information about the changes. You can use the Diff operation to view detailed information about these changes. * * * ### Fix Mistakes Let's assume you have made many changes to your working copy, but now you don't want these changes. In this case, the Revert operation will help you. The Revert operation resets the modifications to the working copy. It can reset one or more files/directories. Of course, it can also reset the entire working copy. In this case, the Revert operation will destroy the pending changes list and restore the working copy to its original state. * * * ### Resolve Conflicts Conflicts may occur during merging. The Merge operation automatically handles things that can be safely merged. Others are treated as conflicts. For example, the file "hello.c" is modified on one branch and deleted on another branch. This situation requires manual handling. The Resolve operation is used to help users identify conflicts and tell the repository how to handle these conflicts. * * * ### Commit Changes The Commit operation is used to transfer changes from the working copy to the repository. This operation modifies the content of the repository, and other developers can view these changes by updating their working copies. Before committing, you must add files/directories to the pending changes list. The list records the changes that will be committed. When committing, we usually provide a comment to explain why these changes were made. This comment also becomes part of the repository's history. Commit is an atomic operation, meaning it either succeeds completely or fails and rolls back. Users will not see a situation where only half of the commit is successful.