DynamoDB - AWS CLI - batch-write-item only inserts one row

Question

I created a table using this AWS CLI command:

aws dynamodb create-table --table-name test_table --attribute-definitions AttributeName=time_stamp,AttributeType=N AttributeName=watch_uuid,AttributeType=S --key-schema AttributeName=watch_uuid,KeyType=HASH AttributeName=time_stamp,KeyType=RANGE --billing-mode PROVISIONED --provisioned-throughput ReadCapacityUnits=1,WriteCapacityUnits=1

I then tried inserting two rows using this command:

aws dynamodb batch-write-item --request-items file://items.json.1.batch.write.txt

and this file contents:

{
    "test_table": [
        {
            "PutRequest": {
                "Item": {
                    "owner_name": {
                        "S": "Test watch 3"
                    },
                    "time_stamp": {
                        "N": "1541524533453"
                    },
                    "watch_uuid": {
                        "S": "A9A0E8B2-CD8D-464A-8787-383A85919A06_1541524533453_Test watch 3"
                    },
                    "y_user_accel": {
                        "S": "0.07286"
                    }
                }
            },
            "PutRequest": {
                "Item": {
                    "owner_name": {
                        "S": "Test watch 4"
                    },
                    "time_stamp": {
                        "N": "1541524533765"
                    },
                    "watch_uuid": {
                        "S": "A9A0E8B2-CD8D-464A-8787-383A85919A06_1541524533453_Test watch 4"
                    },
                    "y_user_accel": {
                        "S": "0.07286"
                    }
                }
            }
        }
    ]
}

I got no errors or indications that it would only insert 1 row, but the DB now only has 1 row. I have tried playing around with the structure of the file to no avail. I either get an error (because the structure was wrong) or only one row of data inserted.

I have also tried changing the provisioning numbers from 1 to 25. This also hasn't helped.

I am pretty sure the problem is in the file structure, but the documentation is inconsistent with what the structure should be.

Any thoughts would be much appreciated. Thanks.

Answer 1

Looking at the example in the official documentation, you need to change your format to this:

{
    "test_table": [
        {
            "PutRequest": {
                "Item": {
                    "owner_name": {
                        "S": "Test watch 3"
                    },
                    "time_stamp": {
                        "N": "1541524533453"
                    },
                    "watch_uuid": {
                        "S": "A9A0E8B2-CD8D-464A-8787-383A85919A06_1541524533453_Test watch 3"
                    },
                    "y_user_accel": {
                        "S": "0.07286"
                    }
                }
            }
         },
         {
            "PutRequest": {
                "Item": {
                    "owner_name": {
                        "S": "Test watch 4"
                    },
                    "time_stamp": {
                        "N": "1541524533765"
                    },
                    "watch_uuid": {
                        "S": "A9A0E8B2-CD8D-464A-8787-383A85919A06_1541524533453_Test watch 4"
                    },
                    "y_user_accel": {
                        "S": "0.07286"
                    }
                }
            }
        }
    ]
}

Note how "test_table" is an array. You need to provide multiple items in that array. You were providing a single item in that array, with two parameters, both named "PutRequest", so when the JSON was parsed it ended up with a single "PutRequest" because you can't have multiple properties on a JSON object with the same name.