|
public Case ( |
||
| whenClauses | ||
| Результат | ||
internal static HqlExpression ToArithmeticExpression(this HqlTreeNode node)
{
var hqlBooleanExpression = node as HqlBooleanExpression;
if (hqlBooleanExpression != null)
{
var builder = new HqlTreeBuilder();
return(builder.Case(new[] { builder.When(hqlBooleanExpression, builder.True()) }, builder.False()));
}
return((HqlExpression)node);
}
public static HqlExpression ConvertBooleanToCase(HqlExpression node)
{
if (node is HqlBooleanExpression)
{
var builder = new HqlTreeBuilder();
return builder.Case(
new[] {builder.When(node, builder.True())},
builder.False());
}
return node;
}
public override NHibernate.Hql.Ast.HqlTreeNode BuildHql(System.Reflection.MethodInfo method, System.Linq.Expressions.Expression targetObject, System.Collections.ObjectModel.ReadOnlyCollection <System.Linq.Expressions.Expression> arguments, NHibernate.Hql.Ast.HqlTreeBuilder treeBuilder, NHibernate.Linq.Visitors.IHqlExpressionVisitor visitor)
{
//return treeBuilder.Constant(0);
return(treeBuilder.Case(new HqlWhen[] {
treeBuilder.When(
treeBuilder.LessThan(visitor.Visit(arguments[0]).AsExpression(), visitor.Visit(arguments[1]).AsExpression()),
treeBuilder.Constant(-1)),
treeBuilder.When(
treeBuilder.GreaterThan(visitor.Visit(arguments[0]).AsExpression(), visitor.Visit(arguments[1]).AsExpression()),
treeBuilder.Constant(1))
},
treeBuilder.Constant(0)));
}
public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject, ReadOnlyCollection<Expression> arguments, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
{
// Instance CompareTo() or static string.Compare()?
Expression lhs = arguments.Count == 1 ? targetObject : arguments[0];
Expression rhs = arguments.Count == 1 ? arguments[0] : arguments[1];
HqlExpression lhs1 = visitor.Visit(lhs).AsExpression();
HqlExpression rhs1 = visitor.Visit(rhs).AsExpression();
HqlExpression lhs2 = visitor.Visit(lhs).AsExpression();
HqlExpression rhs2 = visitor.Visit(rhs).AsExpression();
// CASE WHEN (table.[Name] = N'Foo') THEN 0
// WHEN (table.[Name] > N'Foo') THEN 1
// ELSE -1 END
return treeBuilder.Case(
new[]
{
treeBuilder.When(treeBuilder.Equality(lhs1, rhs1), treeBuilder.Constant(0)),
treeBuilder.When(treeBuilder.GreaterThan(lhs2, rhs2), treeBuilder.Constant(1))
},
treeBuilder.Constant(-1));
}
