How to Create Table in DynamoDB: Syntax and Example

To create a table in DynamoDB, use the CreateTable operation specifying the TableName, KeySchema, and AttributeDefinitions. You also set the ProvisionedThroughput to define read and write capacity units.

Syntax

The CreateTable operation requires these main parts:

• TableName: The name of your table.
• KeySchema: Defines the primary key with AttributeName and KeyType (HASH for partition key, RANGE for sort key).
• AttributeDefinitions: Lists attributes used in the key schema with their data types.
• ProvisionedThroughput: Sets read and write capacity units for the table.

json

{
  "TableName": "string",
  "KeySchema": [
    { "AttributeName": "string", "KeyType": "HASH" | "RANGE" }
  ],
  "AttributeDefinitions": [
    { "AttributeName": "string", "AttributeType": "S" | "N" | "B" }
  ],
  "ProvisionedThroughput": {
    "ReadCapacityUnits": number,
    "WriteCapacityUnits": number
  }
}

Example

This example creates a table named Users with a partition key UserId of type string and sets provisioned throughput.

javascript

const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB({ region: 'us-east-1' });

const params = {
  TableName: 'Users',
  KeySchema: [
    { AttributeName: 'UserId', KeyType: 'HASH' }
  ],
  AttributeDefinitions: [
    { AttributeName: 'UserId', AttributeType: 'S' }
  ],
  ProvisionedThroughput: {
    ReadCapacityUnits: 5,
    WriteCapacityUnits: 5
  }
};

dynamodb.createTable(params, (err, data) => {
  if (err) {
    console.error('Error creating table:', err);
  } else {
    console.log('Table created successfully:', data.TableDescription.TableName);
  }
});

Output

Table created successfully: Users

Common Pitfalls

Common mistakes when creating DynamoDB tables include:

• Not defining the KeySchema correctly (missing HASH key or wrong KeyType).
• Attribute types in AttributeDefinitions not matching the key schema attributes.
• Setting ProvisionedThroughput too low or forgetting it (for on-demand tables, this is not needed).
• Using reserved words as attribute names.

Always double-check your key schema and attribute definitions before creating the table.

javascript

/* Wrong: Missing HASH key in KeySchema */
const wrongParams = {
  TableName: 'WrongTable',
  KeySchema: [
    { AttributeName: 'UserId', KeyType: 'RANGE' } // HASH key missing
  ],
  AttributeDefinitions: [
    { AttributeName: 'UserId', AttributeType: 'S' }
  ],
  ProvisionedThroughput: {
    ReadCapacityUnits: 5,
    WriteCapacityUnits: 5
  }
};

/* Right: Include HASH key */
const rightParams = {
  TableName: 'RightTable',
  KeySchema: [
    { AttributeName: 'UserId', KeyType: 'HASH' }
  ],
  AttributeDefinitions: [
    { AttributeName: 'UserId', AttributeType: 'S' }
  ],
  ProvisionedThroughput: {
    ReadCapacityUnits: 5,
    WriteCapacityUnits: 5
  }
};

Quick Reference

Parameter	Description	Example
TableName	Name of the table	Users
KeySchema	Defines primary key attributes and types	[{AttributeName: 'UserId', KeyType: 'HASH'}]
AttributeDefinitions	Attributes used in keys with data types	[{AttributeName: 'UserId', AttributeType: 'S'}]
ProvisionedThroughput	Read and write capacity units	{ReadCapacityUnits: 5, WriteCapacityUnits: 5}

Key Takeaways

Always define a partition key (HASH) in the KeySchema when creating a DynamoDB table.

AttributeDefinitions must match the attributes used in the KeySchema with correct data types.

ProvisionedThroughput sets the read/write capacity and is required unless using on-demand mode.

Avoid using reserved words as attribute names to prevent errors.

Use AWS SDK methods like createTable with proper parameters to create tables programmatically.