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Posted to notifications@ignite.apache.org by GitBox <gi...@apache.org> on 2021/04/14 15:32:04 UTC
[GitHub] [ignite] ptupitsyn commented on a change in pull request #8999: IGNITE-14523 .NET: Add string.Compare support to LINQ provider
ptupitsyn commented on a change in pull request #8999:
URL: https://github.com/apache/ignite/pull/8999#discussion_r613354601
##########
File path: modules/platforms/dotnet/Apache.Ignite.Linq/Impl/MethodVisitor.cs
##########
@@ -329,6 +331,50 @@ private static void AppendAdjustment(CacheQueryExpressionVisitor visitor, int[]
visitor.Parameters.Add(paramValue);
}
+ /// <summary>
+ /// Get IgnoreCase parameter for string.Compare method
+ /// </summary>
+ /// <param name="expression"></param>
+ /// <returns></returns>
+ private static bool GetStringCompareIgnoreCaseParameter(Expression expression)
+ {
+ if (expression is ConstantExpression constant)
+ {
+ if (constant.Value is bool ignoreCase)
+ {
+ return ignoreCase;
+ }
+ }
+
+ throw new ArgumentException("ignoreCase");
+ }
+
+ /// <summary>
+ /// Visits string.Compare method
+ /// </summary>
+ /// <param name="expression"></param>
+ /// <param name="visitor"></param>
+ private static void VisitStringCompare(MethodCallExpression expression, CacheQueryExpressionVisitor visitor, bool ignoreCase)
+ {
+ visitor.ResultBuilder.Append("casewhen(");
+ if (ignoreCase) visitor.ResultBuilder.Append("lower(");
+ visitor.Visit(expression.Arguments[0]);
+ if (ignoreCase) visitor.ResultBuilder.Append(")");
+ visitor.ResultBuilder.Append(" = ");
+ if (ignoreCase) visitor.ResultBuilder.Append("lower(");
+ visitor.Visit(expression.Arguments[1]);
+ if (ignoreCase) visitor.ResultBuilder.Append(")");
+ visitor.ResultBuilder.Append(", 0, casewhen(");
+ visitor.ResultBuilder.Append("lower(");
Review comment:
The difference is caused by the fact that this `string.Compare` overload is culture-specific (uses `CultureInfo.CurrentCulture`).
I don't think we should try to mimic this behavior when translating to SQL.
Let's keep it simple, [like EF Core does](https://docs.microsoft.com/en-us/ef/core/miscellaneous/collations-and-case-sensitivity#translation-of-built-in-net-string-operations for equality `EF Core makes no attempt to translate simple equality to a database case-sensitive operation`.
* If `ignoreCase` is set - use `lower`, otherwise don't.
* Alternatively, drop the support for this overload to avoid confusion, keep only `Compare(string, string)`
##########
File path: modules/platforms/dotnet/Apache.Ignite.Linq/Impl/MethodVisitor.cs
##########
@@ -329,6 +331,50 @@ private static void AppendAdjustment(CacheQueryExpressionVisitor visitor, int[]
visitor.Parameters.Add(paramValue);
}
+ /// <summary>
+ /// Get IgnoreCase parameter for string.Compare method
+ /// </summary>
+ /// <param name="expression"></param>
+ /// <returns></returns>
+ private static bool GetStringCompareIgnoreCaseParameter(Expression expression)
+ {
+ if (expression is ConstantExpression constant)
+ {
+ if (constant.Value is bool ignoreCase)
+ {
+ return ignoreCase;
+ }
+ }
+
+ throw new ArgumentException("ignoreCase");
+ }
+
+ /// <summary>
+ /// Visits string.Compare method
+ /// </summary>
+ /// <param name="expression"></param>
+ /// <param name="visitor"></param>
+ private static void VisitStringCompare(MethodCallExpression expression, CacheQueryExpressionVisitor visitor, bool ignoreCase)
+ {
+ visitor.ResultBuilder.Append("casewhen(");
+ if (ignoreCase) visitor.ResultBuilder.Append("lower(");
+ visitor.Visit(expression.Arguments[0]);
+ if (ignoreCase) visitor.ResultBuilder.Append(")");
+ visitor.ResultBuilder.Append(" = ");
+ if (ignoreCase) visitor.ResultBuilder.Append("lower(");
+ visitor.Visit(expression.Arguments[1]);
+ if (ignoreCase) visitor.ResultBuilder.Append(")");
+ visitor.ResultBuilder.Append(", 0, casewhen(");
+ visitor.ResultBuilder.Append("lower(");
Review comment:
The difference is caused by the fact that this `string.Compare` overload is culture-specific (uses `CultureInfo.CurrentCulture`).
I don't think we should try to mimic this behavior when translating to SQL.
Let's keep it simple, [like EF Core does](https://docs.microsoft.com/en-us/ef/core/miscellaneous/collations-and-case-sensitivity#translation-of-built-in-net-string-operations for equality `EF Core makes no attempt to translate simple equality to a database case-sensitive operation`.
* If `ignoreCase` is `true` - use `lower`, otherwise don't.
* Alternatively, drop the support for this overload to avoid confusion, keep only `Compare(string, string)`
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