In a recent new release, Oracle has introduced Oracle Database 21c “cloud-first” on Oracle Cloud for Database Cloud Service (Virtual Machine and Bare Metal) and Always Free Autonomous Database Service in some regions. However, It is yet to be released for on-premise and other cloud services.
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In this blog, I am going to cover all the new major features of Oracle Database 21c such as Blockchain tables, SQL Macros, In-memory hybrid scans, and much more.
- What’s New in 21c?
- Oracle Database 21c Overview
- Blockchain Tables
- SQL Macros
- Native JSON Datatype
- In-memory Hybrid Scans
- Execute Javascript Inside Database
- Where Is 20c? What Is An Innovation Release?
What’s New in 21c?
Starting with Oracle Database 20c and now in Oracle Database 21c, a multitenant container database is the only supported architecture from now on. In the previous releases, Oracle supported non-container databases (non-CDBs), but they are no longer supported from 20c onwards.
CDBs: Container Databases
A CDB contains one or more PDBs created by customers and application containers. At the physical level, a CDB is a set of files: control file, online redo log files, and data files.
PDBs: Pluggable Databases
A PDB is a portable collection of schemas, schema objects, and non-schema objects that appears to an application as a separate database. At the physical level, each PDB has its own set of data files that store the data for the PDB. The CDB includes all the data files for the PDBs contained within it and metadata for the CDB itself.
To move or archive a PDB, you have to unplug it first. An unplugged PDB consists of the PDB data files and a metadata file. An unplugged PDB needs to be plugged into a CDB before you can use it.
Oracle Database 21c Overview
Oracle Database 21c is now available “cloud-first” in the Oracle Cloud Database Service on Virtual Machine (for RAC and single instance) and Bare Metal (single instance) and also available in Always Free Autonomous Database Service in Ashburn (IAD), Phoenix (PHX), Frankfurt (FRA), and London (LHR) regions. It will be made generally available for on-prem platforms (including Exadata, Linux, and Windows) in 2021.
Oracle Database 21c is a converged multi-model, multitenant, and multi-workload database. It can be used for any type of data (like documents, objects, graphs, XML, JSON) and any type of workload (like OLTP, analytics, IoT).
Converged Database
A converged database is a database that can support all modern data types and mixed workloads. Converged databases support Spatial data, JSON, IoT, in-memory technologies, and of course, traditional relational data.
Multi-model
It provides native support for multiple data models and access methods within a single database. This approach simplifies data integration across multiple data formats.
Multitenant
It supports Database Container Architecture where every Oracle database must contain or be able to be contained by another database providing database consolidation, isolation, and agility.
Multi-workload
Converged Database can run all types of and mixed workloads such as IoT, Blockchain, Real-Time Analytics and, Machine Learning and these different kinds of database workloads require different kinds of software optimizations.
Major New Features
In this blog, we will discuss a subset of what’s new in Oracle Database 21c starting with some significant new features.
- Blockchain tables
- SQL Macros
- Native JSON datatype
- In-Memory Hybrid Scans
- Execute JavaScript inside
Blockchain Tables
Blockchain as a technology is popular for solving many of the problems associated with the verification of transactions. Introducing Blockchain tables in Oracle Database 21c allows implementing a centralized data model where everyone in the blockchain network has access to the same tamper-resistant tables. Blockchain tables are insert-only tables in which only insert operations are allowed and deleting rows is either prohibited or restricted based on time.
Blockchain tables organize rows into a number of chains where each row in a chain, except the first row, is chained to the previous row in the chain by using a cryptographic hash. A hash value that is part of the row metadata is used to chain and validate rows to ensure that rows can no longer be changed at a later date. Users can also optionally sign the row data with the PKI signatures to protect against users or admins impersonating a different database user.
SQL Macros
SQL Macros are used to break down common SQL expressions and statements into reusable, parameterized modules, which can then be used in any SQL statement. SQL macros are primarily about simplifying and modularizing complex SQL code and they are great for writing clear SQL code. Some of the use cases are functional overloading and simpler code migrations. For example, changes to the code can be managed centrally.
SQL macros can be created with a CREATE (OR REPLACE) FUNCTION command, the ALTER and DROP commands can also be used.
SQL macros are of two types – scalar (SCALAR) and one for tables (TABLE).
- Scalar expressions are typically used in SELECT lists, WHERE, GROUP BY, and HAVING clauses to encapsulate calculations and business logic.
- Table expressions, on the other hand, can be used in a FROM clause.
Native JSON Datatype
Oracle Database 21c has introduced a Native data type called JSON for storing JSON data. Until now VARCHAR2, CLOB, and BLOB datatypes were used to store JSON data. This is optimized for query and DML processing making it faster to process JSON documents. It provides a substantial increase in query and update performance.
This improve read and update operations 4 or 5 times faster and updates to very large JSON documents 20 to 30 times faster as the parsing is done only on an insert operation, no need to parse JSON on read or update operations.
In-Memory Hybrid Scans
Oracle Database In-Memory provides a unique dual-format architecture that enables data to be simultaneously populated in memory in both a row format (in the buffer cache) and a new in-memory column format. The Oracle Database query optimizer automatically routes analytic queries to the column format and OLTP (online transaction processing) queries to the row format, transparently delivering best-of-both-worlds performance. You can specify the INMEMORY attribute for individual columns in an internal table.
It is not always possible to have every column of every table in the Column Store due to memory limitations. Many a time if there is a query that references data(columns) from Column Store which does not exist in memory or data available only in the row store, then the query would run against the row store data and would skip columnar data.
Starting with Oracle Database 21c users can now use both! The optimizer can now scan the In-Memory Column Store and fetch required column values from the row store if needed. This results in significant performance improvements.
Execute JavaScript Inside Oracle Database
With Oracle Database 21c, you can now run JavaScript code snippets inside your database. It is also possible to execute PL/SQL and SQL from JavaScript. This allows them to execute short computational tasks easily expressed in JavaScript, without having to move the data to a mid-tier or browser.
Since the Multilingual Engine (MLE) in Oracle Database 21c automatically maps the Oracle database datatypes to JavaScript data types, it helps developers not to deal with data type conversions themselves.
The DBMS_MLE package allows users to execute JavaScript code inside the Oracle Database and exchange data seamlessly between PL/SQL and JavaScript. With the DBMS_MLE package, developers can write their data processing logic in JavaScript.
Where Is 20c? What Is An Innovation Release?
Oracle Database 20c was only a preview release and not designed for production deployment, also the upgrades to and from 20c are no longer supported. Oracle Database 21c is known to be an innovation release with interesting new features and enhancements. For Long Term Support, if you are upgrading it is still recommended to upgrade to 19c.
Read our blog to know how to Create Oracle Autonomous Data Warehouse 19c on OCI
An Innovation Release has 2 years of Premier Support but there is no Extended Support. A Long Term Support Release has 5 years of Premier Support followed by 3 years of Extended Support is provided.
Conclusion
In this blog, I have covered a brief overview of Oracle Database 21c and its related concepts. I have also covered the major new features introduced in this release such as Blockchain tables, SQL Macros, Native JSON datatype, In-memory Hybrid scans, and Javascript execution inside the database. In addition to these, there are other new features introduced in Oracle Database 21c such as In-Database Machine learning, AutoML, Optimized graph models, and much more.
If you like to read more about new features in Oracle Database 21c, I suggest you read the Oracle official documentation Learning Database New Features
Related/References
- Oracle Cloud Database Deployment Options (VMDB, BMDB, ExaCC, ExaCS & Autonomous (ADW, ATP)
- How To Create Database on Oracle’s Gen2 Cloud (OCI)
- Overview of Autonomous Databases – Oracle Serverless Database
- Roles & Responsibilities of Oracle Cloud DBA
- [1Z0-931-20] Oracle Autonomous Database Cloud 2020 Specialist Everything You Must Know About
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