- Home
- Database Management Systems
Database Management Systems
How data is stored, indexed and queried reliably — from B+ trees to SQL joins and transactions.
SQL Joins (INNER, LEFT, RIGHT, FULL)
Combine rows from two tables. Watch each join type match rows, fill in NULLs, and build its result table in 3D.
Functional Dependencies, Closure & Candidate Keys
A → B means A decides B. Grow the closure X⁺ one dependency at a time to find out whether X is a key, then find every candidate key.
Normalization (1NF, 2NF, 3NF)
Remove redundancy from tables step by step. Watch one messy table split into clean 1NF, 2NF and 3NF tables in 3D — and see which duplicate values disappear.
Transactions & ACID
Why a bank transfer never loses money even when the server crashes. See atomicity, consistency, isolation and durability in four 3D scenarios.
Conflict Serializability
Is an interleaved schedule as safe as running the transactions one by one? Draw an edge for every conflict and look for a cycle.
B+ Tree Indexing
The data structure behind database indexes. Insert keys, watch nodes split and the tree grow upward, and run range queries along the linked leaves.
Relational Algebra (Select and Project)
The maths behind SQL. Filter rows with selection σ, pick columns with projection π, and see duplicates disappear.
Deadlock Detection (Wait-For Graph)
Transactions that wait for each other forever form a cycle. Watch a depth-first search find it and the database abort a victim.
About Database Management Systems
Databases stay fast and correct thanks to a few clever ideas. See a B+ tree split and grow as keys are inserted, normalise a messy table into 1NF, 2NF and 3NF, watch every SQL join type build its result row by row, and follow transactions through crashes, recovery and locks to understand ACID. Relational algebra and deadlock detection explain how queries are built and how locks go wrong.