B+ tree index structure in DBMS Theory - Mini Project: Build & Apply

Building a Simple B+ Tree Index Structure

📖 Scenario: You are working as a database assistant helping to organize data for faster searching. You will build a simple B+ tree index structure step-by-step to understand how data is stored and searched efficiently.

🎯 Goal: Create a basic B+ tree index structure with nodes and keys, configure the tree order, insert keys into the tree nodes, and finalize the tree with leaf node links.

📋 What You'll Learn

Create a B+ tree node data structure with keys and children

Set the order (maximum number of keys) of the B+ tree

Insert keys into the B+ tree nodes following B+ tree rules

Link leaf nodes to form a linked list for efficient range queries

💡 Why This Matters

🌍 Real World

B+ trees are used in databases and file systems to quickly find data by indexing keys.

💼 Career

Understanding B+ trees helps in database design, optimization, and working with large data storage systems.

1

Create B+ Tree Node Data Structure

Create a class called BPlusTreeNode with an __init__ method that initializes two attributes: keys as an empty list and children as an empty list.

DBMS Theory

# Your code here
class BPlusTreeNode:
    def __init__(self):
        self.keys = []
        self.children = []

Need a hint?

Think of a B+ tree node as a container that holds keys and pointers to child nodes.

2

Set B+ Tree Order

Create a variable called order and set it to 3 to define the maximum number of keys a B+ tree node can hold.

DBMS Theory

class BPlusTreeNode:
    def __init__(self):
        self.keys = []
        self.children = []

# Set the order of the B+ tree
order = 3

Need a hint?

The order controls how many keys each node can hold before splitting.

3

Insert Keys into B+ Tree Node

Create a function called insert_key that takes a node and a key as parameters. Insert the key into the node.keys list while keeping the keys sorted.

DBMS Theory

class BPlusTreeNode:
    def __init__(self):
        self.keys = []
        self.children = []

order = 3

def insert_key(node, key):
    # Your code here

Need a hint?

Adding a key and sorting keeps the node's keys in order for efficient searching.

4

Link Leaf Nodes

Add an attribute called next to the BPlusTreeNode class and initialize it to None. This will link leaf nodes together for easy traversal.

DBMS Theory

class BPlusTreeNode:
    def __init__(self):
        self.keys = []
        self.children = []
        # Your code here

order = 3

def insert_key(node, key):
    node.keys.append(key)
    node.keys.sort()

Need a hint?

Leaf nodes in a B+ tree are linked like a chain to allow quick range queries.