TODO.md

QueryLeaf Project TODO List

Integration Tests

We've implemented the following tests:

Simple Queries

• Test SELECT with multiple column aliases (implemented and working)
• Test SELECT with arithmetic operations in projections
• Test SELECT with multiple WHERE conditions connected by OR (implemented and working)
• Test SELECT with IN operator (implemented and working)
• Test SELECT with NOT IN operator
• Test SELECT with NULL/NOT NULL checks
• Test SELECT with LIMIT and OFFSET
• Test SELECT with ORDER BY multiple fields
• Test SELECT with ORDER BY ASC/DESC combinations

Nested Field Access

• Test querying on deeply nested fields (3+ levels deep)
• Test projecting multiple nested fields simultaneously (implemented, working with fixes)
• Test filtering with comparisons on nested fields (implemented, working with fixes)
• Test updating nested fields
• Test nested field access with complex WHERE conditions (implemented, working with fixes)

Array Access

• Test querying arrays with multiple indices (implemented, working with fixes)
• Test filtering by array element properties at different indices (implemented, working with fixes)
• Test filtering by multiple array elements simultaneously
• Test projecting multiple array elements in one query
• Test array access with nested arrays
• Test updating array elements

GROUP BY

• Test GROUP BY with multiple columns (implemented, working with fixes)
• Test GROUP BY with HAVING clause
• Test GROUP BY with multiple aggregation functions
• Test aggregation functions: AVG, MIN, MAX, COUNT (implemented, working with fixes)
• Test GROUP BY with ORDER BY on aggregation results
• Test GROUP BY with complex expressions
• Test GROUP BY with filtering before aggregation
• Test GROUP BY on nested fields
• Test performance with large dataset aggregation

JOINs

• Test INNER JOIN with multiple conditions
• Test LEFT OUTER JOIN implementation
• Test RIGHT OUTER JOIN implementation
• Test FULL OUTER JOIN implementation
• Test JOIN with WHERE conditions
• Test multiple JOINs in one query (3+ tables)
• Test JOINs with aggregation
• Test JOINs with nested field access
• Test JOINs with array field access
• Test performance with large dataset JOINs

Advanced Features

• Test CASE statements in SELECT list
• Test subqueries in WHERE clause
• Test subqueries in FROM clause
• Test window functions if supported
• Test date/time functions
• Test string functions

Edge Cases

• Test handling of special characters in field names
• Test handling of extremely large result sets
• Test behavior with invalid SQL syntax
• Test behavior with valid SQL but unsupported features
• Test behavior with missing collections
• Test behavior with invalid data types
• Test handling of MongoDB ObjectId conversions

Performance Testing

• Benchmark simple queries vs native MongoDB queries
• Benchmark complex queries vs native MongoDB queries
• Benchmark with increasing dataset sizes (10K, 100K, 1M documents)
• Identify bottlenecks in the translation process
• Optimize query execution for common patterns

Documentation

• Document SQL syntax support and limitations
• Create examples of each supported SQL feature
• Document MongoDB query translation for each SQL feature
• Create a troubleshooting guide
• Add inline code documentation

Feature Enhancements

• Add support for SQL DISTINCT
• Implement SQL subquery support
• Support for data types (DATE, TIMESTAMP, BOOLEAN)
• Add basic transaction support
• Support for SQL UNION, INTERSECT, EXCEPT
• Add index creation/management via SQL
• Implement execution plan visualization
• Add query caching
• Support for conditional expressions (CASE)
• Add execution metrics and query profiling