The advent of cloud services has changed the way we build web applications. This in turn changed the responsibilities of a web developer.
We used to integrate everything into a single web application on a single server. This included various responsibilities such as storage, databases, authentication, background jobs, caching and more.
Cloud services allow us to reduce the complexity of our applications and web servers by offloading responsibility to these highly available, scalable and durable cloud services.
We call a web developer who knows how to deploy and integrate cloud services with a web applicationCloud Engineer.
If you want to accelerate your web development career in 2020, this is theAWS Developer Associate certificationcan help you achieve this ultimate goal.
The main AWS service you need to study to pass the AWS Developer Associate exam is DynamoDB. So I released what I callÖFinaleDynamoDB-Spickzettelfor free. You can print it out on the day of the exam to increase your chances of passing.
ErasNaderthe AWS Developer Advocate for AWS Amplify who suggested I release my entire cheat sheet for free. Without him, this function would not exist.
ErasChurchthe senior AWS technologist specializing in DynamoDB who volunteered his time to ensure the accuracy of this cheat sheet. This went from 5 pages to 8 pages! ?????????
If you have twitter please do me a favor by thanking them by tweeting at@dabit3e@NoSQLKnowHowcom a hashtag #AWSCertified.
So let's get to the cheat sheet:
DynamoDB basics
DynamoDB-Nameis a fully managed NoSQL key/value and document database.
DynamoDB is suitable for workloads with any amount of data thatrequire predictable read and write performanceand automatic scaling from large to small and everywhere in between.
DynamoDB scales up and down to support anyRead and write capacity that you specifyper second in provisioned capacity mode. Or you can set it up for on-demand mode and there's little or no capacity planning.
- DynamoDB storage3 copies of dataon SSD drivesthrough 3 AZsin a region.
- The most common DynamoDB data types areB(Binary),N(number) andS(Corda)
- The tables consist ofArticle(rows) and articles consist ofAttribute(Columns)
Consistency of reads and writes
DynamoDB can be configured to supportFinally consistent readings(Default) andStrongly consistent readingsby phone call.
Finally consistent readingsThe data is returned immediately, but the data may be inconsistent. Data copies are generally consistent within 1 second.
Strongly consistent readsalways reads from the leader partition because it always has a current copy. Data will never be inconsistent, but latency can be higher. Data copies will be consistent with a 1 second guarantee.
partitions
APartitionThis is when DynamoDB splits your table into smaller chunks of data. This speeds up reading very large tables.
DynamoDB automatically creates partitions for:
- Every 10 GB of data
- If you exceed the RCUs (3000) or WCUs (1000) limits for a single partition
- If DynamoDB detects an active partition pattern, that partition will be split to fix the problem.
DynamoDB will tryequally distributedthe RCUs and WCUs on the partitions
Primary Key Theme
Define the primary keyswhere and howYour data is stored in partitions
The key scheme can consist of two keys:
- Partition Key (PK) is also referred to asHashish
- Ö Sort Key (SK) is also known asAREA
For example by using the AWS DynamoDB API. CLI, SDK refer to PK and SK by their aliases for legacy reasons.
There are two types of primary keys:
- SimplyPrimary key (using only one partition key)
- composedPrimary key (using a partition and sort key)
The uniqueness of the key is as follows:
- When creating a simple primary key, the PKValue can be unique
- When creating a composite primary keythe combination of PK and SK must be unique
Using a sort key logically groups the records in the partition in ascending order.
secondary indices
DynamoDB has two types of indexes:
- LSI- Local secondary index
- GSI- Global Secondary Index
LSI - local secondary index
- Supportsstarkor all consistency readings
- Can only be created with the source table (cannot be modified or dropped unless you also drop the table)
- Composite only
- 10GB or less per partition
- Share capacity units with base table
- It must share the partition key (PK) with the base table.
GSI - Global Secondary Index
- Any consistencyreads (may not provide strong consistency)
- Can create, change or delete at any time
- simple and composed
- Can have any attributes such as Primary Key (PK) or Secondary Key (SK).
- No size limit per partition
- Has its own capacity settings (does not share with the base table)
Scan
Your table(s) should be designed such that your primary workload access patterns do not use scanning. Overall, scans should be required in moderation, e.g. B. for rare reports.
- Examines all items in a table and returns one or more items through filters
- By default, all attributes for each element are returned (useproject printoutBorder)
- Scans are sequential and you can speed up a scan with parallel scans usingsectioneoverall segments
- Scans can be slow, especially for very large tables, and can easily eat up your provisioned throughput.
- Scans are one of the most expensive ways to access data in DynamoDB.
Advice
- Find items based on primary key values
- The table must have a composite key to perform queries
- Finally, by default, queries are consistent (useConsistentRead TrueChange Strongly Consistent)
- By default, returns all attributes for each element found by a query (useproject printoutBorder)
- By default it is sorted in ascending order (useScanIndexForwardto False to reverse the order to descending)
capacity modes
DynamoDB has two capacity modes,Providedeupon request. You can switch between these modesonce every 24 hours.
Provided
Provisioned Throughput Capacityis the maximum allowed capacity of your appread or write per seconda table or an index
- Providedis suitable for predictable or stable workloads
- remote controlsis the read capacity unit
- WCUsis the unit of absorption capacity
You must enable Auto Scaling with Provisionedcapacity mode. In this mode you define a lower and upper limit for the capacity that the table should support. DynamoDB automatically adds and removes capacity between these values on your behalf and throttles calls that exceed the cap for too long.
If you exceed your provisioned capacity, you will receive an exception:ProvisionedThroughputExceededException(Drown)
Strangulationand whenRequests are blockeddue to read or write frequency exceeding defined limits. For example. Exceeding defined provisioned capacity, partition split, discrepancy between table and index capacity.
upon request
capacity as requiredIt is paid per request. So you only pay for what you use.
- On Demand is suitable forNovoorunpredictableworkload
- Throughput is limited only by the default table limits (40,000 RCUs and 40,000 WCUs).
- There may be restrictionsif you exceed twice your previous peak capacity (high water mark) in 30 minutes. For example, if you previously peaked at 30,000 operations/sec, you might not peak at 90,000 operations/sec immediately, but you might peak at 60,000 operations/sec.
- Since there is no fixed limitOn-demand can get very expensivebased on emerging scenarios
Calculate reads and writes
Calculate measured values (RCU)
One unit reading capacityRepresentative:
- a strongly consistent reading per second,
- or two possibly consistent readings per second,
- for an item up to 4 KB in size.
Prepare how RCUs are calculatedStrength
- Round the dates up to the nearest 4.
- Divide the data by 4
- times per number of readings
Here is an example:
- 50 readings from 40 KB per article. (40/4) x 50 = 500 RCUs
- 10 readings from 6 KB per item. (8/4) x 10 = 20 RCUs
- 33 readings of 17 KB per article. (20/4) x 33 = 132 RCUs
Prepare how RCUs are calculatedpossible
- Round the dates up to the nearest 4.
- Divide the data by 4
- times per number of readings
- Divide the last number by 2
- Round to the nearest whole number
Here is an example:
- 50 readings from 40 KB per article. (40/4) x 50/2 = 250 RCUs
- 11 readings of 9 KB per article. (12/4) x 11/2 = 17 RCUs
- 14 readings of 24 KB per article. (24/4) x 14/2 = 35 RCUs
Calculate records (Records)
One unit recording capacityRepresentative:
- one write per second,
- for an item up to 1 KB
how to calculatehe writes
- Round the data up to the nearest 1.
- Times by number of writes
Here is an example:
- 50 recordings of 40 KB each. 40 x 50 = 2000 WCUs
- 11 grava a 1 KB por item. 1 x 11 = 11 WCUs
- 18 writes at 500 BYTES per element. 1 x 18 = 18 WCUs
Accelerator for DynamoDB
Accelerator for DynamoDB(DAX)It is afully managed in-memory write-through cachefor DynamoDB running on a cluster
- Finally, the readings are consistent
- Incoming requests are evenly distributed to all cluster nodes.
- DAX can improve read response times formicroseconds
DAX is ideal for:
- fastest possible response times
- Apps that read a small number of articles more often
- Apps that areintensive reading
DAX is not ideal for:
- Applications that require highly consistent reads
- Applications that do not require read response times in the microsecond range
- Apps that arewrite intensely, or who don't read much
- If you don't need DAXconsider using ElastiCache
DynamoDB transactions
DynamoDB supports transactions over theTransactWriteItemseTransactGetItemsAPI calls.
transactionsThey can query multiple tables at once and are an all-or-nothing approach (all API calls must succeed).
global tables
DynamoDB Global Tables provide a fully managed solution for deploymentmultiregional and multimaster databases.
flows
Fluxos make DynamoDByou can configure a Lambda function to be triggered whenever data changes in a table to respond to changes.Streams do not consume RCUs.
API for DynamoDB
Most notable DynamoDB API commands via CLI:aws dynamodb <comando>
aws dynamodbget item returns a set of attributes for the element with the given primary key. If there is no matching item, no data is returned and the response does not contain an Item element.
aws dynamodbset article Creates a new item or replaces an old item with a new one. If an item with the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item.
aws dynamodbupdate article Edits the attributes of an existing element or adds a new element to the table if it doesn't already exist.
aws dynamodbBatch-Get-Itemreturns the attributes of one or more elements from one or more tables. You identify the items requested by the primary key. A single operation can restore up to16 MB of data, which can contain up to100 Article.
aws dynamodbbatch write itemadds or deletes multiple elements in one or more tables. You can write up16 MB of data, which can include up to25 Insert or Delete Requests. Individual articles can be writtenup to 400 KB in size.
aws dynamodbcreate the tableadds a new table to your account. Table names must be unique within each region.
aws dynamodbupdate tableChanges provisioned throughput settings, global secondary indexes, or DynamoDB Streams settings for a specific table.
aws dynamodbDelete table The operation deletes a table and all of its elements.
aws dynamodbtransact-get-items is a synchronous operation that atomically retrieves multiple items from one or more tables (but not indexes) in a single account and region. The call can contain up to25 objects. The total size of the items in the transactionmust not exceed 4 MB.
aws dynamodbtransact-write-items a synchronous write operation that groups up to25 requests for action. These actions can target items in different tables, but not different AWS accounts or Regions, and no two actions can target the same item.
aws dynamodbAdvice finds items based on primary key values. You can query the table or the secondary index with a composite primary key.
aws dynamodbScan returns one or more elements and element attributes by accessing each element in a table or secondary index.
? #rocketsToMars
I want to help you break into the web and cloud industry. That's why I'm posting mineBuch AWS Developer Associate Certification 2020Course on the freeCodeCamp YouTube channel with over 10 hours of additional content that I have never published before.
This free course will be released in a few days while I put the finishing touches on it.
I believe in bringing tech education to the world because the more we improve our skills, the sooner we can lift people out of poverty, the sooner we can develop sustainable solutions to keep our planet green and healthy, and the more Previous We can launch rockets to Mars.
FAQs
What are the key three attributes of DynamoDB? ›
In DynamoDB, tables, items, and attributes are the core components that you work with. A table is a collection of items, and each item is a collection of attributes. DynamoDB uses primary keys to uniquely identify each item in a table and secondary indexes to provide more querying flexibility.
How many ways can Amazon DynamoDB retrieve data from a DynamoDB table? ›- ExecuteStatement retrieves a single or multiple items from a table. ...
- GetItem – Retrieves a single item from a table. ...
- Query – Retrieves all of the items that have a specific partition key. ...
- Scan – Retrieves all of the items in the specified table.
DynamoDB supports the Java Set , List , and Map collection types. The following table summarizes how these Java types map to the DynamoDB types.
How do I practice DynamoDB? ›- Basic concepts in DynamoDB.
- Prerequisites - getting started tutorial.
- Step 1: Create a table.
- Step 2: Write data to a table using the console or AWS CLI.
- Step 3: Read data from a table.
- Step 4: Update data in a table.
- Step 5: Query data in a table.
- Step 6: Create a global secondary index.
Can a DynamoDB table have multiple partition keys? While you can only have a single partition key per DynamoDB table, you can create global indexes that have a different partition key than the table itself. This is useful if you want to query your data in a different way than the primary table.
How many types of primary keys does DynamoDB? ›There are two types of primary keys in DynamoDB: Partition key: This is a simple primary key. If the table has only a partition key, then no two items can have the same partition key value. Composite primary key: This is a combination of partition key and sort key.
Is DynamoDB easy to learn? ›It is a very simple and small API that follows key-value method to store, access and perform advanced data retrieval. DynamoDB comprises of three fundamental units known as table, attribute, and items.
Can we use SQL Query for DynamoDB? ›In Amazon DynamoDB, you can use either the DynamoDB API, or PartiQL, a SQL-compatible query language, to query an item from a table.
What is the most efficient way to Query DynamoDB? ›The only way to effectively and efficiently query DynamoDB data in AWS is to export it to a system that handles a full SQL dialect and can query the data in a way that is not painfully slow. The two best options for the destination system are: Amazon Redshift, which has its own storage mechanism for data.
What are the 3 main data types? ›- a whole number, which we call the integer type.
- a real number, which we call the double type.
- a truth value representing TRUE or FALSE, which R calls the logical type. These are also often called the boolean type, especially in other programming languages.
- a character sequence, which R calls the character type.
What are the 3 basic data types? ›
Most programming languages support basic data types of integer numbers (of varying sizes), floating-point numbers (which approximate real numbers), characters and Booleans.
How long does it take to learn DynamoDB? ›Start with an interactive knowledge check, and after you've completed the courses, take the post-assessment to see what you've learned. Duration: 16 hours, optional self-paced labs: 9 hours. There are optional (paid) labs associated with each course.
What is DynamoDB not good for? ›When not to use DynamoDB: When multi-item or cross table transactions are required. When complex queries and joins are required. When real-time analytics on historic data is required.
How many tables should I have in DynamoDB? ›As a general rule, you should maintain as few tables as possible in a DynamoDB application. To better understand why that is (keeping few tables, ideally only one) and why it might be beneficial, let's briefly review the DynamoDB data model.
Can a DB have 2 primary keys? ›Each table can only have one primary key. Access can automatically create a primary key field for you when you create a table, or you can specify the fields that you want to use as the primary key.
Can you join two tables in DynamoDB? ›Since DynamoDB is a NoSQL database, it does not allow you to perform "join" queries on multiple tables. A join requires the DMBS to scan several tables and perform complex processing to aggregate the data to return a result set. DynamoDB was built to provide quick, single-digit responses no matter how big the dataset.
Can you Query multiple keys in DynamoDB? ›Querying is a very powerful operation in DynamoDB. It allows you to select multiple Items that have the same partition ("HASH") key but different sort ("RANGE") keys.
What are the 5 types of primary key? ›- Primary Key. The primary key refers to a column or a set of columns of a table that helps us identify all the records uniquely present in that table. ...
- Super Key. ...
- Candidate Key. ...
- Alternate Key. ...
- Foreign Key. ...
- Composite Key. ...
- Unique Key.
Hash key in DynamoDB
The primary reason for that complexity is that you cannot query DynamoDB without the hash key. So, it's not allowed to query the entire database. That means you cannot do what you would call a full table scan in other databases.
The maximum item size in DynamoDB is 400 KB, which includes both attribute name binary length (UTF-8 length) and attribute value lengths (again binary length). The attribute name counts towards the size limit.
Is DynamoDB SQL or NoSQL? ›
DynamoDB is a proprietary NoSQL database by Amazon that supports key-value and document data offered via the Amazon Web Services. This AWS cloud-only offering provides a scalable, highly available, and secure managed database platform for any application.
Can DynamoDB handle big data? ›DynamoDB is a key-value and document database that can support tables of virtually any size with horizontal scaling. This enables DynamoDB to scale to more than ten trillion requests per day with peaks greater than 20 million requests per second, over petabytes of storage.
Which is better MongoDB or DynamoDB? ›MongoDB supports more native data types than DynamoDB, and it lets you nest documents. Systems Design: Beyond accommodating large volumes of rapidly changing structured, semi-structured and unstructured data, MongoDB enables developers to add to the schema as their needs change.
Is DynamoDB a JSON database? ›As mentioned before, DynamoDB is a key-value store database that uses a documented-oriented JSON data model.
What query language does DynamoDB use? ›Amazon DynamoDB supports PartiQL , a SQL-compatible query language, to select, insert, update, and delete data in Amazon DynamoDB.
Does DynamoDB store data as JSON? ›Answer. DynamoDB stores data in a tabular format, where each item in a table is represented as a set of key-value pairs. To store JSON data in DynamoDB, you can use the PutItem , UpdateItem , or BatchWriteItem operations to add or modify items in a table and include the JSON data as one of the attributes in the item.
Is MongoDB faster than DynamoDB? ›MongoDB stores query data in RAM which means query performance is significantly better than what you would find with Dynamo. So if speed is a concern for your app, MongoDB may be the best choice.
Is S3 faster than DynamoDB? ›2) Amazon S3 vs DynamoDB: Purpose
For relatively small items, especially those with a size of less than 4 KB, DynamoDB runs individual operations faster than Amazon S3. DynamoDB can scale on-demand, but S3 offers better scalability.
DynamoDB is lightning fast (faster than MongoDB) so DynamoDB is often used as an alternative to sessions in scalable applications. DynamoDB best practices also suggests that if there are plenty of data which are less being used, move it to other table.
Is DynamoDB frontend or backend? ›DynamoDB is a great tool not only for frontend developers but for all the other people who work with a database from frontend developers to database administrators and non-IT professionals to IT consultants.
How many writes can DynamoDB handle? ›
Each partition on a DynamoDB table is subject to a hard limit of 1,000 write capacity units and 3,000 read capacity units. If the workload is unevenly distributed across partitions, or if the workload relies on short periods of time with high usage (a burst of read or write activity), the table might be throttled.
Does DynamoDB have a REST API? ›In this article you will create a REST API integrated with Amazon DynamoDB using AWS Amplify including CRUD operations and publication. Access to the REST API will allow both registered users and guests. In order to test it you will create a client including an authentication flow using Vue.
What are the 4 common data types? ›4 Types of Data: Nominal, Ordinal, Discrete, Continuous | upGrad blog.
What are the 4 essential data types? ›A data type is a classification of data which tells the compiler or interpreter how the programmer intends to use the data. Most programming languages support various types of data, including integer, real, character or string, and Boolean.
What are the 2 main types of data? ›There are two general types of data – quantitative and qualitative and both are equally important. You use both types to demonstrate effectiveness, importance or value.
Can I learn AWS in 3 months? ›If you are aiming for a specialty certification, I highly recommend earning your AWS Solution Architect – Associate certification first to ensure your foundational knowledge of basic AWS concepts. It took me three months with seven hours/week of study, to pass the AWS Certified Data Analytics – Specialty certification.
Is DynamoDB hard? ›Designing a DynamoDB-backed Architecture is Not Easy
DynamoDB may be simple to interact with, but a DynamoDB-backed architecture is absolutely not simple to design. DynamoDB is a key-value store. It works really well if you are retrieving individual records based on key lookups.
- Limited Querying Options. ...
- Difficult To Predict Costs. ...
- Unable to Use Table Joins. ...
- Limited Storage Capacities For Items. ...
- On-Premise Deployments.
Amazon DynamoDB's Data Model
DynamoDB uses three basic data model units, Tables, Items, and Attributes. Tables are collections of Items, and Items are collections of Attributes.
DynamoDB operates on data stored on the disk, but there is also a possibility to store data in RAM. DynamoDB has a few specific features which make it a rapid database. It's a much faster database compared to any popular relational database that uses SSD to store the data.
How many indexes can DynamoDB have? ›
Each table in DynamoDB can have up to 20 global secondary indexes (default quota) and 5 local secondary indexes. For more information about the differences between global secondary indexes and local secondary indexes, see Improving data access with secondary indexes.
How many tables we can create in DynamoDB? ›DynamoDB increased the default quota for the number of DynamoDB tables you can create and manage per AWS account and AWS Region from 256 to 2,500 tables. DynamoDB also increased the number of table management operations you can perform concurrently from 50 to 500.
Is DynamoDB key value or wide column? ›Amazon DynamoDB is a key/value as well as a document store and Apache HBase is a key/value store.
What is an attribute in DynamoDB? ›In Amazon DynamoDB, an item is a collection of attributes. Each attribute has a name and a value. An attribute value can be a scalar, a set, or a document type. For more information, see Amazon DynamoDB: How it works. DynamoDB provides four operations for basic create, read, update, and delete (CRUD) functionality.
How many attributes does a DynamoDB table have? ›There is no limit to the number of attributes but the total item size is limited to 400kb. The maximum item size in DynamoDB is 400 KB, which includes both attribute name binary length (UTF-8 length) and attribute value lengths (again binary length).
What are the properties of DynamoDB? ›- DynamoDBGlobalSecondaryIndexHashKey. Maps a class property to the partition key of a global secondary index. ...
- DynamoDBGlobalSecondaryIndexRangeKey. ...
- DynamoDBHashKey. ...
- DynamoDBIgnore. ...
- DynamoDBLocalSecondaryIndexRangeKey. ...
- DynamoDBProperty. ...
- DynamoDBRenamable. ...
- DynamoDBRangeKey.
How many attributes does DynamoDB allows? Explanation: DynamoDB allows 20 attributes.
What kind of data can be stored in DynamoDB? ›DynamoDB supports three data types (number, string, and binary), in both scalar and multi-valued sets. It supports document stores such as JSON, XML, or HTML in these data types. Tables do not have a fixed schema, so each data item can have a different number of attributes.
Can you Query DynamoDB without primary key? ›Hash key in DynamoDB
The primary reason for that complexity is that you cannot query DynamoDB without the hash key. So, it's not allowed to query the entire database. That means you cannot do what you would call a full table scan in other databases.
There are tables in Amazon DynamoDB and each table has several items (rows) and each item has Keys and Attributes (Columns).
How many columns can you have in DynamoDB? ›
What is the DynamoDB column limit? DynamoDB does not contain columns within its database structure. Therefore, there is no column limit for DynamoDB databases. However, the database design requires the users to store data as items that may have single or multiple attributes.
How many tables can we create in DynamoDB? ›Well, yes, there is only one table.
What are the limitations of DynamoDB? ›DynamoDB transactional API operations have the following constraints: A transaction cannot contain more than 100 unique items. A transaction cannot contain more than 4 MB of data. No two actions in a transaction can work against the same item in the same table.
Can DynamoDB handle millions of records? ›DynamoDB is a key-value and document database that supports tables of virtually any size with horizontal scaling. DynamoDB scales to more than 10 trillion requests per day and with tables that have more than ten million read and write requests per second and petabytes of data storage.
Can you store objects in DynamoDB? ›DynamoDB is a document or NoSQL database. Although it can be used for the storage of binary objects, it was designed for the storage of structured textual/JSON data. It can store individual items of up to 400 KB in size. The items are stored in tables, which can be located in a particular region or replicated globally.
How many requests can DynamoDB handle? ›Fast and flexible NoSQL database service for any scale
DynamoDB can handle more than 10 trillion requests per day and can support peaks of more than 20 million requests per second.
How many attributes/columns can DynamoDB have? As there are no columns in DynamoDB, You can add a new item with a new attribute. An item can have one or more attributes. The maximum number of attributes per item must be 400KB.