Standardize LIKE In Jakarta Query: SQL & NoSQL Pattern Matching

by Pedro Alvarez 64 views

Hey guys! Let's dive into a crucial topic for Java and NoSQL developers using Jakarta Query: standardizing the LIKE operator syntax. Currently, SQL databases have a pretty consistent LIKE operator, but when you jump into the NoSQL world, it's like the Wild West! This article explores the challenges and potential solutions for achieving cross-store compatibility in Jakarta Query.

The Problem: Inconsistent LIKE Syntax Across Databases

So, the main issue is this: while SQL databases generally follow a standard LIKE syntax with % (multi-character wildcard) and _ (single-character wildcard), NoSQL databases are all over the place. Some don't even have a direct equivalent to LIKE! Others use regex-based matching, which can be tied to specific programming languages. Even when a LIKE-style operator does exist, the syntax and how it works can be totally different.

For us Java/NoSQL developers, this is a pain. We want a consistent way to perform pattern matching, just like we have with operators like >, <, and so on. Jakarta Query aims to provide a unified query language, but without a defined LIKE-style syntax, we're stuck with:

  • Writing different queries for different databases: Talk about a headache! This defeats the purpose of a unified query language.
  • Losing portability in cross-store queries: If you're querying multiple databases, your LIKE expressions might not work the same way everywhere.
  • Unexpected differences due to provider-specific behavior: This can lead to bugs and inconsistencies that are hard to track down.

Let's look at some examples to illustrate the problem:

PostgreSQL (SQL)

SELECT * FROM customers WHERE name LIKE 'John%';

In PostgreSQL, like most SQL databases:

  • % matches zero or more characters. For example, 'John%' would match 'John', 'Johnny', 'John Smith'. It's super flexible for finding names that start with "John", or even just contain "John" somewhere if you use '%John%'.
  • _ matches exactly one character. So, 'John_' would match 'John ' or 'John1', but not 'Johnny'. This is great for enforcing specific length patterns.

MongoDB (NoSQL) – Regex-Based

db.customers.find({ name: { $regex: "^John", $options: "i" } });

MongoDB uses regular expressions for pattern matching. This gives you a ton of power, but it's also more complex than the simple LIKE syntax:

  • ^John matches strings that start with "John". The ^ is a regex anchor that means "beginning of the string."
  • `$options: