---
title: "Define slicing"
subject: "Data Mining"
chapter: 2
key: "semester_7/data_mining:define-slicing"
source: https://www.bctengineer.com/q/semester_7/data_mining/define-slicing
site: BCT Engineering
---

# Define slicing

Data Mining · Chapter 2: Data Pre-processing

- Asked in: year not given
- Video: [OLAP operations with real life example | Data Warehouse](https://www.youtube.com/watch?v=BLqE2EKiAy4) — Gate Smashers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/data_mining/define-slicing
- Whole chapter: https://www.bctengineer.com/md/semester_7/data_mining/chapter-2

## Question

Define slicing with example.

## Short answer

Slicing is an OLAP operation that selects one value on one dimension of a data cube, producing a sub-cube with one dimension fewer. Example: slicing a sales cube by time = 'Q1' gives a two-dimensional item-versus-location table for Q1 only.

## Answer

**Slicing** is an OLAP operation that selects **one value on one dimension** of a data cube, producing a sub-cube (a "slice") with one dimension fewer. It is like a WHERE condition on a single dimension.

**Example**: sales cube with dimensions time (quarter), item (type) and location (city). Slice with `time = "Q1"` returns a two-dimensional table of item vs location showing the sales of Q1 only.

```text
 Cube(time, item, location)  --slice time=Q1-->  Table(item, location)
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does slicing do to a data cube?
   A. Selects one value on one dimension, giving a sub-cube with one fewer dimension
   B. Selects values on two or more dimensions, keeping all dimensions
   C. Moves from summary to detail
   D. Aggregates over all dimensions into a single value
   Answer: A. Slice fixes one dimension value, like a WHERE condition on a single dimension. (Key point: Slice definition)

2. Slicing a (time, item, location) cube with time = Q1 gives what?
   A. A 3-D cube of Q1 and Q2
   B. A 2-D table of item vs location for Q1
   C. A single grand total
   D. A table of time vs item for all locations
   Answer: B. Fixing time removes that dimension, leaving item vs location. (Key point: Slice example)

3. Which feature distinguishes slice from dice?
   A. Slice raises dimensions; dice reduces them
   B. Slice uses hierarchy; dice does not
   C. Slice picks a single value on one dimension; dice picks on two or more
   D. No difference
   Answer: C. Dice uses conditions on several dimensions and keeps the dimension count. (Key point: Slice vs dice)