Shopspring decimal support

[El-76]

shopspring.Decimal / NullDecimal mappings to DECIMAL and MONEY, supports queries, in / out parameters, tvp and bulk copy.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.48%. Comparing base (8c35947) to head (09a3511).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #287      +/-   ##
==========================================
+ Coverage   75.27%   75.48%   +0.20%     
==========================================
  Files          33       34       +1     
  Lines        6500     6579      +79     
==========================================
+ Hits         4893     4966      +73     
- Misses       1323     1326       +3     
- Partials      284      287       +3     

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[Copilot]

Pull Request Overview

This PR adds support for shopspring.Decimal and NullDecimal types in the go-mssqldb driver, enabling seamless integration with SQL Server's DECIMAL and MONEY data types. The implementation provides comprehensive support for queries, input/output parameters, table-valued parameters (TVP), and bulk copy operations.

Key changes include:

• Integration of shopspring/decimal package for precise decimal arithmetic
• Introduction of Money[D] generic type supporting both Decimal and NullDecimal
• Complete test coverage for all decimal/money operations including edge cases

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
go.mod	Adds shopspring/decimal dependency
money.go	Introduces Money[D] generic type with Value() and Scan() methods
mssql.go	Adds makeParam support for decimal types
mssql_go19.go	Implements makeMoneyParam and extends makeParamExtra for decimal handling
bulkcopy.go	Adds bulk copy support for Money types and decimal string parsing
queries_test.go	Adds comprehensive test coverage for decimal parameter operations
queries_go19_test.go	Extensive tests for input/output decimal parameters with encoding scenarios
tvp_go19_db_test.go	Table-valued parameter tests with decimal support and scaling
bulkcopy_test.go	Bulk copy tests for decimal and money types
money_test.go	Unit tests for Money type operations and parameter creation
internal/decimal/decimal.go	Exposes GetInteger method for internal decimal access
README.md	Documents new decimal and money type support

[Copilot]

Remove the unnecessary semicolon at the end of the return statement. Go doesn't require semicolons at the end of statements.

[Copilot]

The decimal rescaling logic is duplicated multiple times in this test file. Consider extracting this into a helper function to reduce code duplication and improve maintainability.

[Copilot]

The null handling for decimal.NullDecimal and Money[decimal.NullDecimal] is identical. Consider consolidating this logic to avoid duplication and ensure consistent behavior.

[shueybubbles]

it's nice that this module doesn't bring it a bunch of other stuff.
It'd be nice if the driver supported a pluggable type system like we support different network protocols for SQL connections so apps could include the module of their choice to get the implementation. #Resolved

[El-76]

I think there is already some work done in sql library itself, but its still considered experimental, see: golang/go#30870 .

Source code:

% fgrep -A 3 'type decimal interface {' src/database/sql/convert.go 
type decimal interface {
	decimalDecompose
	decimalCompose
}

[shueybubbles]

ecimal.NullDecimal]

i think this is the first use of generics in the driver #Resolved

[shueybubbles]

[El-76]

@apoorvdeshmukh @stuartpa please consider taking a look.