AWS DynamoDB Attribute Data Types

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Published on August 13, 2020

AWS DynamoDB supports 10 different data types for attribute values in a table. They are :

  • Number
  • String
  • Boolean
  • Null
  • Binary
  • List
  • Map
  • Number Set
  • String Set
  • Binary Set

1) Number Data Type — N

The number data type represented by N is used to store a number.

  • Number can be positive, negative or zero.
  • Number can be integer or float (up to 38 digits of precision).
  • To maximize compatibility, DynamoDB sends numbers across the network as strings. However internally they are treated as numbers while performing calculations.
  • Leading and trailing zeros are truncated.
10

15.5

-23.76676786768778

0

2) String Data Type — S

The string data type represented by S is used to store a UTF-8 encoded string.

Hello

Wat's up

3) Boolean Data Type — BOOL

The boolean data type represented by BOOL is used to store a boolean value — either true or false.

true

false

4) Null Data Type — NULL

The null data type represented by NULL is used to store a value that is null, undefined or signifies an unknown state.

  • Values allowed can be either true (representing a null) or false (representing not null).
true

false

5) Binary Data Type — B

The binary data type represented by B is used to store binary data like base64 encoded image data, encrypted data etc.

bXkgc3VwZXIgc2VjcmV0IHRleHQh==

6) List Data Type — L

The list data type represented by L is used to store an ordered collection of values. This is similar to a JSON array.

  • Order of values is preserved.
  • Values of any data type can be stored. Items in the list can be of different types if required.
["Tree", "Sand"]

["Hello", "World", 100.54]

7) Map Data Type — M

The map data type represented by M is used to store an unordered collection of name-value pairs. This is similar to a JSON object.

  • Map is ideal for saving JSON data / document in DynamoDB.
  • Nested values can go up to 32 levels deep.
{
	"address": {
		"street_1": "19th Main",
		"street_2": "",
		"city": "Bangalore",
		"state": "KA" 
	}
}

8) Number Set Data Type — NS

The number set data type represented by NS is used to store a set of numbers.

  • Only numeric values are allowed. No other data type is allowed.
  • Each value must be unique within the set.
  • Order of values is not preserved.
  • Empty number set is not supported.
[42.2, -19, 7.5, 3.14]

9) String Set Data Type — SS

The string set data type represented by SS is used to store a set of UTF-8 strings.

  • Only string values are allowed. No other data type is allowed.
  • Each value must be unique within the set.
  • Order of values is not preserved.
  • Empty string set is not supported.
["Black", "Green", "Red"]

10) Binary Set Data Type — BS

The binary set data type represented by BS is used to store a set of binary values.

  • Each value must be unique within the set.
  • Order of values is not preserved.
  • Empty binary set is not supported.
["U3Vubnk=", "UmFpbnk=", "U25vd3k="]
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