Convert SQL queries to Arel where feasible #453
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- Add ArelHelpers module for building Arel queries - Convert simple queries in numeric_deterministic_ordering.rb - Convert queries in finders.rb and hash_tree_support.rb - Fix table access patterns to use model context properly - Apply RuboCop corrections to all modified files All multi-database tests passing
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Pull Request Overview
This PR converts hardcoded SQL queries to Arel for improved type safety, database portability, and maintainability. The changes focus on query builders for hierarchical tree operations while preserving complex database-specific optimizations as raw SQL.
- Added ArelHelpers module with utility methods for building hierarchy queries using Arel
- Converted multiple SQL query methods to use Arel including stats queries, complex joins, and generation-based finders
- Updated table access patterns to properly use hierarchy_class and model tables with proper aliasing
Reviewed Changes
Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| lib/closure_tree/support.rb | Includes the new ArelHelpers module in the Support class |
| lib/closure_tree/arel_helpers.rb | New helper module providing Arel query building utilities |
| lib/closure_tree/numeric_deterministic_ordering.rb | Converts ordering and stats queries from SQL to Arel |
| lib/closure_tree/hierarchy_maintenance.rb | Updates hierarchy deletion to use Arel helper method |
| lib/closure_tree/hash_tree_support.rb | Converts tree scope generation depth queries to Arel |
| lib/closure_tree/finders.rb | Converts generation-based and leaves finder queries to Arel |
Comments suppressed due to low confidence (2)
lib/closure_tree/hash_tree_support.rb:10
- [nitpick] The variable name
hierarchy_table_arelis redundant since it's already clear it's an Arel table. Consider renaming tohierarchy_tableto match the pattern used in other methods.
hierarchy_table_arel = if scope.respond_to?(:hierarchy_class)
lib/closure_tree/hash_tree_support.rb:18
- [nitpick] The variable name
model_table_arelis redundant since it's already clear it's an Arel table. Consider renaming tomodel_tableto match the pattern used in other methods.
model_table_arel = scope.klass.arel_table
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| query = hierarchy_table | ||
| .project( | ||
| hierarchy_table[:ancestor_id].count.as('total_descendants'), |
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The count operation should count all rows, not just ancestor_id values. This should be hierarchy_table.project(Arel.star).count.as('total_descendants') or use a literal count(*) to match the original SQL behavior.
| hierarchy_table[:ancestor_id].count.as('total_descendants'), | |
| hierarchy_table.project(Arel.star).count.as('total_descendants'), |
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lib/closure_tree/arel_helpers.rb
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| # Build the middle subquery with DISTINCT | ||
| middle_subquery = Arel::SelectManager.new | ||
| middle_subquery.from(inner_subquery) | ||
| middle_subquery.project(Arel.sql('DISTINCT descendant_id')) |
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Using raw SQL for DISTINCT defeats the purpose of using Arel. This should use Arel's distinct method: middle_subquery.project(inner_subquery[:descendant_id]).distinct.
| middle_subquery.project(Arel.sql('DISTINCT descendant_id')) | |
| middle_subquery.project(inner_subquery[:descendant_id]).distinct |
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| join_roots = model_table | ||
| .join(roots_subquery) | ||
| .on(Arel.sql('1 = 1')) |
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[nitpick] Using raw SQL '1 = 1' for a cross join condition is not idiomatic Arel. Consider using a proper cross join or documenting why this cartesian product is intentional.
| join_roots = model_table | |
| .join(roots_subquery) | |
| .on(Arel.sql('1 = 1')) | |
| join_roots = Arel::Nodes::JoinSource.new( | |
| model_table, | |
| roots_subquery | |
| ) |
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- Use Arel.star.count instead of counting specific column for SQL COUNT(*) - Replace raw SQL 'DISTINCT' with Arel's .distinct method - Document intentional use of cartesian product join in find_all_by_generation These changes improve code consistency while maintaining the same functionality. All tests pass with these modifications.
Summary
This PR converts hardcoded SQL queries to Arel where it makes sense, improving type safety, database portability, and maintainability.
Changes
_ct_sum_order_byto use Arelself_and_descendants_preorderedandroots_and_descendants_preorderedfind_all_by_generation(instance and class methods) to Arelleavesmethod to use Arel joinsdefault_tree_scopeto use Arel for subqueries and joinshierarchy_classand model tablesmodel_classto proper context in instance methodsNotes
find_by_pathkept as SQL due to complexityBenefits