Why Boolean and binary types in Elasticsearch? - Purpose & Use Cases

The Big Idea

Discover how simple true/false and raw data types can supercharge your search and storage!

The Scenario

Imagine you have a huge list of items and you want to mark each as either true or false, or store small pieces of data like images or files. Doing this by hand means writing long, complicated code to handle each case separately.

The Problem

Manually managing true/false values or binary data is slow and error-prone. You might mix up data formats, waste space, or make your searches very slow because the system doesn't understand your data type well.

The Solution

Boolean and binary types in Elasticsearch let you store true/false values and raw binary data efficiently. Elasticsearch knows exactly how to handle these types, making your searches faster and your data storage simpler.

Before vs After

✗ Before

PUT my_index/_doc/1
{
  "active": "true"
}

✓ After

PUT my_index/_doc/1
{
  "active": true
}

What It Enables

It enables lightning-fast filtering and accurate storage of true/false flags and binary data, making your search and data handling smarter and more efficient.

Real Life Example

For example, an online store can quickly filter products that are in stock (true) or out of stock (false), or store product images as binary data directly in Elasticsearch.

Key Takeaways

Boolean and binary types simplify storing true/false and raw data.

They improve search speed and reduce errors.

They make your data handling smarter and more efficient.

Practice

1. What type of data does the boolean type in Elasticsearch store?

easy

A. True or false values

B. Text strings

C. Numbers with decimals

D. Base64 encoded files

Solution

1. Step 1: Understand the boolean type purpose

   The boolean type is designed to store values that represent true or false states.

2. Step 2: Compare with other data types

   Text strings, numbers, and base64 encoded files are stored in different types like text, float, or binary, not boolean.

3. Final Answer:

   True or false values -> Option A

4. Quick Check:

   Boolean = true/false [OK]

Hint: Boolean means true or false only [OK]

Common Mistakes:

• Confusing boolean with text or number types
• Thinking boolean stores encoded files
• Assuming boolean can hold multiple values

2. Which of the following is the correct way to define a binary field in an Elasticsearch mapping?

easy

A. {
"my_field": {"type": "text"}
}

B. {
"my_field": {"type": "boolean"}
}

C. {
"my_field": {"type": "binary"}
}

D. {
"my_field": {"type": "integer"}
}

Solution

1. Step 1: Identify the binary type syntax

   In Elasticsearch, a binary field is defined with "type": "binary" inside the mapping.

2. Step 2: Check other options

   Options A, B, and D define other types (text, boolean, integer) which are not binary.

3. Final Answer:

   { "my_field": {"type": "binary"} } -> Option C

4. Quick Check:

   Binary type uses "type": "binary" [OK]

Hint: Binary type always uses "type": "binary" in mapping [OK]

Common Mistakes:

• Using boolean or text instead of binary
• Missing quotes around type name
• Incorrect JSON structure

3. Given this Elasticsearch document mapping and data:

{
  "mappings": {
    "properties": {
      "is_active": {"type": "boolean"},
      "file_data": {"type": "binary"}
    }
  }
}

Document:
{
  "is_active": true,
  "file_data": "SGVsbG8gd29ybGQ="
}

What will be the value of is_active when retrieved?

medium

A. null

B. true

C. false

D. "SGVsbG8gd29ybGQ="

Solution

1. Step 1: Understand the boolean field value

   The field "is_active" is boolean and set to true in the document.

2. Step 2: Confirm retrieval value

   When retrieved, the boolean field returns the stored true value, not the binary data or null.

3. Final Answer:

   true -> Option B

4. Quick Check:

   Boolean field returns true/false as stored [OK]

Hint: Boolean fields return true or false as stored [OK]

Common Mistakes:

• Confusing binary field value with boolean
• Expecting base64 string for boolean field
• Assuming null if not explicitly queried

4. You have this Elasticsearch mapping snippet:

{
  "properties": {
    "flag": {"type": "boolean"},
    "data": {"type": "binary"}
  }
}

Which of the following is a mistake that will cause an error when indexing a document?

medium

A. {"flag": "yes", "data": "dGVzdA=="}

B. {"flag": true, "data": "dGVzdA=="}

C. {"flag": false, "data": ""}

D. {"flag": false, "data": "dGVzdA=="}

Solution

1. Step 1: Check boolean field value types

   The boolean field "flag" must be true or false, not strings like "yes".

2. Step 2: Validate binary field values

   The binary field "data" expects base64 encoded strings, which "dGVzdA==" is valid for.

3. Final Answer:

   {"flag": "yes", "data": "dGVzdA=="} -> Option A

4. Quick Check:

   Boolean must be true/false, not string [OK]

Hint: Boolean fields accept only true or false, not strings [OK]

Common Mistakes:

• Using string 'yes' or 'no' for boolean
• Passing non-base64 strings to binary fields
• Leaving binary field empty without quotes

5. You want to store user profile pictures in Elasticsearch using the binary type and also keep a flag if the user is verified using boolean. Which of the following mapping and document pairs is correct and efficient?

hard

A. {
"mappings": {
"properties": {
"profile_pic": {"type": "text"},
"verified": {"type": "boolean"}
}
}
}

Document:
{
"profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA",
"verified": "yes"
}

B. {
"mappings": {
"properties": {
"profile_pic": {"type": "binary"},
"verified": {"type": "boolean"}
}
}
}

Document:
{
"profile_pic": "not_base64_data",
"verified": true
}

C. {
"mappings": {
"properties": {
"profile_pic": {"type": "binary"},
"verified": {"type": "text"}
}
}
}

Document:
{
"profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA",
"verified": false
}

D. {
"mappings": {
"properties": {
"profile_pic": {"type": "binary"},
"verified": {"type": "boolean"}
}
}
}

Document:
{
"profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA",
"verified": true
}

Solution

1. Step 1: Check mapping types for fields

   The profile picture should be stored as binary type with base64 data, and verified as boolean true/false.

2. Step 2: Validate document values

   { "mappings": { "properties": { "profile_pic": {"type": "binary"}, "verified": {"type": "boolean"} } } } Document: { "profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA", "verified": true } uses binary type with base64 string and boolean true, which is correct and efficient.

3. Step 3: Identify errors in other options

   { "mappings": { "properties": { "profile_pic": {"type": "text"}, "verified": {"type": "boolean"} } } } Document: { "profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA", "verified": "yes" } uses text for binary and string "yes" for boolean, which is incorrect.
   { "mappings": { "properties": { "profile_pic": {"type": "binary"}, "verified": {"type": "text"} } } } Document: { "profile_pic": "iVBORw0KGgoAAAANSUhEUgAAAAUA", "verified": false } uses text for boolean field.
   { "mappings": { "properties": { "profile_pic": {"type": "binary"}, "verified": {"type": "boolean"} } } } Document: { "profile_pic": "not_base64_data", "verified": true } has invalid base64 data for binary field.

4. Final Answer:

   Mapping and document with binary and boolean types correctly used -> Option D

5. Quick Check:

   Binary = base64, Boolean = true/false [OK]

Hint: Binary needs base64 data; boolean must be true or false [OK]

Common Mistakes:

• Using text type for binary data
• Passing non-base64 strings to binary fields
• Using strings like 'yes' for boolean fields