Query Operation For DynamoDB Document Client Class

Query Operation for DynamoDB Document Client Class

Docs and Source

Explanation and Notes

The KeyConditionExpression ”specifies the key values for items to be retrieved by the Query action.”

This is what performs an equality test on a single partition key value. So in my case, I used this to search the partition field.

The ExpressionAttributeNames is a field where you can map the names of the fields you’re querying. So in my case, I used this to map the #pk value to the partition field. This replaces the #pk value with partition at run time. This is required because partition is a reserved keyword in DynamoDB. There are a ton of reserved keywords so this is an important thing to remember.

The ExpressionAttributesValues field maps the :pk value to the value you need in the KeyConditionExpression field. In my case, I used it to map the :pk value to the partition#value value.

Code Example

ddbClient.query({
	TableName: tableName,
	KeyConditionExpression: '#pk = :pk',
	ExpressionAttributeNames: {
	  '#pk': 'partition'
	},
	ExpressionAttributeValues: {
	  ':pk': 'account#fbo'
	},
});

#aws
#dynamodb