What is the Difference Between Cluster and Non Cluster Index?
🆚 Go to Comparative Table 🆚The main difference between clustered and non-clustered indexes lies in how they sort and store data in a table. Here are the key differences between the two:
- Data sorting and storage: A clustered index sorts the data rows in the table based on their key values, while a non-clustered index stores the data at one location and the indices at another location.
- Data pages storage: Clustered indexes store data pages in the leaf nodes of the index, while non-clustered indexes never store data pages in the leaf nodes of the index.
- Memory consumption: Clustered indexes demand less memory to execute operations, while non-clustered indexes demand more memory.
- Speed: Clustered indexes offer faster data access compared to non-clustered indexes.
- Number of indexes: A single table can have only one clustered index, but it can have multiple non-clustered indexes.
- Data storage: Clustered indexes store data on the disk, while non-clustered indexes do not have the inherent ability to store data on the disk.
In summary, clustered indexes are used to define the order or sort the data in a table, storing data pages in the leaf nodes of the index and offering faster data access. On the other hand, non-clustered indexes collect data at one place and store records at another place, demanding more memory and being slower than clustered indexes.
Comparative Table: Cluster vs Non Cluster Index
Here is a table comparing the differences between clustered and non-clustered indexes:
Feature | Clustered Index | Non-Clustered Index |
---|---|---|
Number of indexes | One per table | Multiple per table |
Data storage | Stores data on the disk | Does not store data on the disk |
Main data | Clustered index is the main data | Non-clustered index is a copy of data |
Inherent ability | Physically reorders table records to match index key values | Logically sorts index but not the actual data |
Clustered key | Defines order of data within table | Defines order of data within index |
Index key | Converted to row locator, pointing to data row | Contains both value and pointer to actual row |
Primary key | Can be created automatically for primary key constraints | Multiple non-clustered indexes can be created |
Access speed | Faster than non-clustered indexes | Slower than clustered indexes |
Memory usage | Demands less memory to execute operations | Demands more memory to execute operations |
Data placement | Leaf nodes of the index contain data pages | Leaf nodes of the index contain index rows |
In summary, a clustered index physically reorders table records to match index key values, stores data on the disk, and is faster than non-clustered indexes. On the other hand, non-clustered indexes logically sort the index but not the actual data, do not store data on the disk, and are slower than clustered indexes.
- Clustered vs Nonclustered Index
- Clustering vs Classification
- Cloud Computing vs Cluster Computing
- Indexing vs Sorting
- Glossary vs Index
- Nanoparticles vs Nanoclusters
- Stratified Sampling vs Cluster Sampling
- Hierarchical vs Partitional Clustering
- Index Funds vs Mutual Funds
- Database vs Instance
- Aggregation vs Agglomeration
- Grid Computing vs Cloud Computing
- Distributed Database vs Centralized Database
- Cloud Computing vs Grid Computing
- Volatile vs Nonvolatile
- NoSQL vs MongoDB
- Binary Tree vs Binary Search Tree
- Row vs Column
- Database vs Data Warehouse