Differences between a relational (SQL) database and DynamoDB when creating a table

Tables are the fundamental data structures in relational databases and in Amazon DynamoDB. A relational database management system (RDBMS) requires you to define the table's schema when you create it. In contrast, DynamoDB tables are schemaless—other than the primary key, you do not need to define any extra attributes or data types when you create a table.

The following section compares how you would create a table with SQL to how you would create it with DynamoDB.

Creating a table with SQL

With SQL you would use the CREATE TABLE statement to create a table, as shown in the following example.

CREATE TABLE Music (
    Artist VARCHAR(20) NOT NULL,
    SongTitle VARCHAR(30) NOT NULL,
    AlbumTitle VARCHAR(25),
    Year INT,
    Price FLOAT,
    Genre VARCHAR(10),
    Tags TEXT,
    PRIMARY KEY(Artist, SongTitle)
);

The primary key for this table consists of Artist and SongTitle.

You must define all of the table's columns and data types, and the table's primary key. (You can use the ALTER TABLE statement to change these definitions later, if necessary.)

Many SQL implementations let you define storage specifications for your table, as part of the CREATE TABLE statement. Unless you indicate otherwise, the table is created with default storage settings. In a production environment, a database administrator can help determine the optimal storage parameters.

Creating a table with DynamoDB

Use the CreateTable operation to create a provisioned mode table, specifying parameters as shown following:

{
    TableName : "Music",
    KeySchema: [
        {
            AttributeName: "Artist",
            KeyType: "HASH" //Partition key
        },
        {
            AttributeName: "SongTitle",
            KeyType: "RANGE" //Sort key
        }
    ],
    AttributeDefinitions: [
        {
            AttributeName: "Artist",
            AttributeType: "S"
        },
        {
            AttributeName: "SongTitle",
            AttributeType: "S"
        }
    ],
    ProvisionedThroughput: {       // Only specified if using provisioned mode
        ReadCapacityUnits: 1,
        WriteCapacityUnits: 1
    }
}

The primary key for this table consists of Artist (partition key) and SongTitle (sort key).

You must provide the following parameters to CreateTable: