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In the DynamoDB ecosystem, you work with tables, attributes, and items.

Substitution variables of an expression have a 2MB limit.īefore using DynamoDB, you must familiarize yourself with its basic components and ecosystem. Attribute expressions have a 255-byte limit. Reserved Words − DynamoDB does not prevent the use of reserved words as names.Įxpression Length − Expression strings have a 4KB limit. They use the following characters: AZ, a-z, 0-9, “_”, “-”, and “.”.Īttribute Names − One character remains the minimum, and 64KB the maximum, with exceptions for keys and certain attributes. Table and Secondary Index Names − Names must conform to a minimum of 3 characters in length, and a maximum of 255. Sort Key Length and Values − Its minimum length stands at 1 byte, and maximum at 1024 bytes, with no limit for values unless its table uses a local secondary index. Partition Key Length and Values − Their minimum length sits at 1 byte, and maximum at 2048 bytes, however, DynamoDB places no limit on values.

Projected Secondary Index Attributes Per Table − DynamoDB allows 20 attributes. Secondary Indexes Per Table − Five local and five global are permitted. Table Size and Quantity Per Account − Table sizes have no limits, but accounts have a 256 table limit unless you request a higher cap. Provisioned Throughput Increase and Decrease − You can increase this as often as needed, but decreases remain limited to no more than four times daily per table. In the US, 40K read and write remains the cap per table (80K per account), and other regions have a cap of 10K per table with a 20K account cap. Provisioned Throughput Min/Max − All tables and global secondary indices have a minimum of one read and one write capacity unit. A write capacity unit is a single write per second for items no bigger than 1KB. You can review them from the following points −Ĭapacity Unit Sizes − A read capacity unit is a single consistent read per second for items no larger than 4KB. LimitationsĭynamoDB does suffer from certain limitations, however, these limitations do not necessarily create huge problems or hinder solid development. It also allows simple use of multiple languages: Ruby, Java, Python, C#, Erlang, PHP, and Perl. Its design also supports a wide range of use from lighter tasks and operations to demanding enterprise functionality. It does not force the use of a particular data source and structure, allowing users to work with virtually anything, but in a uniform way. The two main advantages of DynamoDB are scalability and flexibility. It requires specifications (partition key and sort key). It uses a secondary index to achieve the same function. Modifications to it occur automatically on table changes. It uses standard indexes created through SQL statements. It uses SELECT statements and filtering statements. In tables, it uses items made of attributes It only uses primary keys, and no schema on creation. Its fundamental structures are tables, and must be defined. It uses a persistent connection and SQL commands. The following table highlights the differences between DynamoDB and RDBMS − Common Tasks RDBMSĭynamoDB uses a NoSQL model, which means it uses a non-relational system. It automatically distributes data and traffic over servers to dynamically manage each customer's requests, and also maintains fast performance. DynamoDB allows users to create databases capable of storing and retrieving any amount of data, and serving any amount of traffic.