How does Git store data?

Git stores data not as a set of diffs, but as snapshots of the project state.

#Key idea

Each commit is a full snapshot of all project files at the time of the commit. If a file has not changed, Git does not duplicate it, but simply references the already stored version.

#What data in Git consists of

Git stores everything as objects:

1. Blob - file content

Stores only the file's data, without a name or path.

2. Tree - directory structure

Links file and folder names to blobs and other trees.

3. Commit - a snapshot of the project

Contains:

• a reference to a tree (state of the files),
• reference(s) to parent commits,
• author, date, message.

4. Tag - a named reference

Usually points to a specific commit (for example, a release).

#How Git saves space

• unchanged files are not copied;
• hashing (SHA-1 / SHA-256) is used;
• identical content -> the same object.

#Why this matters

• fast operations (commit, checkout, branch);
• data integrity (any change changes the hash);
• branches are just pointers to commits, not copies of code.

#Short version for an interview

Git stores data as a set of project snapshots, using objects (blob, tree, commit), rather than as diffs between versions.