Databases & DBA  

Evolution of Database Systems

Database Management Systems (DBMSs) have been essential to information management for more than 50 years. Despite significant technological advancements and the emergence of various database types (including tree structures, graphs, objects, and documents), the relational model (RM) and Structured Query Language (SQL) remain the dominant approaches. Many believed that newer models, such as NoSQL, would replace them, but that has not happened. Instead, RM systems integrated the new database’s elements, becoming more scalable and faster. 

As per my domain, this article focuses on analytical databases - systems designed to quickly and efficiently organise large volumes of data.

1. Early data models (1960s–2000s)

Hierarchical and network models

The first commercial database systems, such as IBM’s IMS (1968), used a hierarchical model, where data was arranged in tree-like structures. Later, the new network model - CODASYL - was introduced, applying more flexible graph-like connections. These systems performed well and helped to manage the data, but using them appeared to be challenging, as queries required procedural navigation and were manual.  

Emergence of the relational model

The 1970s were an important period for information management, as the RM models emerged, introducing a more mathematically based approach to data. They centred on tables (relations) and declarative querying with SQL, thereby simplifying schema design and portability. This feature made the foundation for modern DBMSs.

Extensions and enhancements

Many technological advancements occurred in the 1980s and '90s: entity-relationship modelling for design, object-oriented for richer data types (arrays, JSON), and object-relational extensions to work with multimedia and spatial data. However, they did not entirely replace RM due to the complexity of migrating applications.

2. Emerging models and the rise of variety (2000s–2020s)

2.1 MapReduce and distributed processing

In 2003, Google’s MapReduce was launched. The application provided a more straightforward way to process and organise data on multiple nodes. This feature led to open-source implementations, for example, Hadoop. Despite the revolutionary nature of the platform, Hadoop’s limitations in expressiveness (it was hard to write and understand) and performance (it was not optimised for interactive or fast querying) could not replace SQL-compatible systems. 

Currently, systems like Apache Spark and Apache Flink continue MapReduce’s legacy, providing richer APIs and better support for analytical requests. They often use SQL as the front-end query language. 

2.2 Key-value stores

Redis, DynamoDB, and RocksDB provided simple key/value access. They are most efficient for caching or high-speed session management, but underperform in analytical tasks. However, many relational DBMSs now embed key/value storage engines to combine transactional and analytical functions. 

2.3 Document stores

MongoDB and Couchbase support semi-structured data based on formats like JSON. The systems are flexible and scalable, especially for web applications; however, the lack of support for joins and complex queries initially made them unsuitable for analytics. Later, nonetheless, they adopted SQL-based querying, indexing, and Online Analytical Processing (OLAP) connectors. That helped blur the line with traditional analytical databases. 

2.4 Column-family databases

Apache Cassandra and HBase, inspired by Google Bigtable, apply wide-column data models suitable for distributed datasets. The platforms perform best in write-heavy environments, as they offer tunable consistency. Integrations with big data processing frameworks, such as Spark, primarily enhance the analytical capabilities of column-family databases. 

2.5 Search and other niche models

Search engines, such as Elasticsearch, are embedded into many analytics stacks. Array databases (SciDB) manage scientific data, vector databases (Milvus) support AI workloads, and graph databases (Neo4j) provide expressive traversal features. Nevertheless, there is a common trend among them: SQL or SQL-based functions are embedded to generate analytics more easily. 

Despite their domain-specific designs, nearly all of these systems are adding SQL-like interfaces to broaden usability and analytics integration.

3. Technical advances in analytical DBMSs

3.1 Column-oriented storage

Moving to columnar storage is one of the most crucial technological developments in analytical databases. Storing data by column rather than row significantly reduces I/O for analytical queries in systems such as Vertica, ClickHouse, and Snowflake. Columnar storage also allows vectorised execution, compression, and parallel scanning, making analytical DBMSs suitable for OLAP processes.

3.2 Cloud-native databases

Cloud systems provide elasticity and separation of storage and computing, changing how analytical databases are built and maintained. Snowflake, Google BigQuery, and Amazon Redshift exemplify this change. Their pay-as-you-go model and auto-scaling have made cloud-native analytics the new standard. 

3.3 Data lakes and lakehouses

Initially, data lakes allowed raw storage of all data types (structured and unstructured) on affordable cloud storage. However, the lack of query optimisation and consistency checks limited their analytical capabilities. Now, the lakehouse architecture (a hybrid approach integrating the lakes’ flexibility with the reliability of warehouses). Delta Lake and Apache Iceberg are now powering SQL-based queries.  

3.4 NewSQL

Google Spanner and CockroachDB are consistent and tolerant of faults. They combine traditional relational DBMSs with horizontally scalable NoSQL stores. These systems are designed to manage transactional workloads globally and incorporate features for live analytics. Rather than replacing RM, they reimplement it for modern architectures.

3.5 Hardware-aware databases

Hardware-aware databases are being tuned to exploit modern hardware, such as NVMe SSDs, GPUs, and FPGAs (modern hardware accelerators). Analytical processes have used in-memory processing, GPU acceleration, and cache-conscious algorithms to reduce latency.

4. Convergence and current trends

Despite decades of diversification, there is a trend towards convergence. 

First, almost all new systems now provide SQL interfaces, even those designed initially without them. Second, multi-model DBMSs (Oracle, PostgreSQL) are becoming the standard, since systems like PostgreSQL and Oracle now support JSON, spatial, graph and full-text search with traditional tabular data. Finally, analytical databases are essential elements of enterprise architecture; their examples are BI applications and embedded dashboards. These databases are fast-performing and allow visual analytics, which is crucial in business. 

5. Challenges and future

The future of analytical databases will depend on how new challenges will be handled; data privacy, complexity, and real-time expectations are among them. 

First of all, the world is becoming increasingly regulated. Therefore, analytical systems must implement controls for access auditing and masking. 

The integration of analytical databases is generally valuable. Nonetheless, supporting multiple data models and query engines adds operational complexity. Most importantly, users now expect insights in seconds, and analytical systems must move towards real-time processing. 

When discussing the future of databases, they will broadly support ML; examples of such systems are BigQuery ML and Snowflake Cortex. Analytical databases with open formats and interoperability will also be available. The first examples of this are Parquet, ORC, and Apache Arrow, which already enable cross-platform analytics with shared datasets. 

Conclusion

The RM and SQL models have proven adaptable and irreplaceable, especially in the analytical domain, where performance and scalability matter the most. Technology integrates into human lives worldwide, hence organisations collect more data and ask more complex questions. Analytical databases have become central to modern information ecosystems to meet the market's requirements. The secret to their success lies in integrating the best innovations (ML and AI) while preserving the foundations.