/// <summary>
/// Creates an argument that creates a lambda expression for extracting the key from a class.
/// </summary>
/// <param name="foreignKeyElement">The unique key element.</param>
/// <returns>An expression that creates a filter for an index.</returns>
public static ExpressionSyntax GetNullableKeyFilter(ForeignElement foreignKeyElement)
{
// Used as a variable when constructing the lambda expression.
string abbreviation = foreignKeyElement.Table.Name[0].ToString(CultureInfo.InvariantCulture).ToLowerInvariant();
// .HasFilter(s => s.Figi != null)
// .HasFilter(p => p.BaseCurrencyCode != null && p.CurrencyCode != null)
BinaryExpressionSyntax syntaxNode = default;
for (int index = 0; index < foreignKeyElement.Columns.Count; index++)
{
// We can only filter nullable items.
if (foreignKeyElement.Columns[0].Column.ColumnType.IsNullable)
{
if (index == 0)
{
syntaxNode = SyntaxFactory.BinaryExpression(
SyntaxKind.NotEqualsExpression,
SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
SyntaxFactory.IdentifierName(abbreviation),
SyntaxFactory.IdentifierName(foreignKeyElement.Columns[0].Column.Name)),
SyntaxFactory.LiteralExpression(
SyntaxKind.NullLiteralExpression));
}
else
{
BinaryExpressionSyntax oldNode = syntaxNode;
syntaxNode = SyntaxFactory.BinaryExpression(
SyntaxKind.LogicalAndExpression,
oldNode,
SyntaxFactory.BinaryExpression(
SyntaxKind.NotEqualsExpression,
SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
SyntaxFactory.IdentifierName(abbreviation),
SyntaxFactory.IdentifierName(foreignKeyElement.Columns[index].Column.Name)),
SyntaxFactory.LiteralExpression(
SyntaxKind.NullLiteralExpression)));
}
}
}
// this.BuyerKey = new UniqueIndex<Buyer>("BuyerKey").HasIndex(b => b.BuyerId);
return(SyntaxFactory.SimpleLambdaExpression(SyntaxFactory.Parameter(SyntaxFactory.Identifier(abbreviation)), syntaxNode));
}
/// <summary>
/// Creates an argument that creates a lambda expression for extracting the key from a class.
/// </summary>
/// <param name="foreignKeyElement">The unique key element.</param>
/// <returns>An argument that extracts a key from an object.</returns>
public static ExpressionSyntax GetForeignKey(ForeignElement foreignKeyElement)
{
// Used as a variable when constructing the lambda expression.
string abbreviation = foreignKeyElement.Table.Name[0].ToString(CultureInfo.InvariantCulture).ToLowerInvariant();
// This will create an expression for extracting the key from record.
CSharpSyntaxNode syntaxNode = null;
if (foreignKeyElement.Columns.Count == 1)
{
// A simple key can be used like a value type.
syntaxNode = SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
SyntaxFactory.IdentifierName(abbreviation),
SyntaxFactory.IdentifierName(foreignKeyElement.Columns[0].Column.Name));
}
else
{
// A Compound key must be constructed from an anomymous type.
List <SyntaxNodeOrToken> keyElements = new List <SyntaxNodeOrToken>();
foreach (ColumnReferenceElement columnReferenceElement in foreignKeyElement.Columns)
{
if (keyElements.Count != 0)
{
keyElements.Add(SyntaxFactory.Token(SyntaxKind.CommaToken));
}
keyElements.Add(
SyntaxFactory.AnonymousObjectMemberDeclarator(
SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
SyntaxFactory.IdentifierName(abbreviation),
SyntaxFactory.IdentifierName(columnReferenceElement.Column.Name))));
}
// b => b.BuyerId or b => new { b.BuyerId, b.ExternalId0 }
syntaxNode = SyntaxFactory.AnonymousObjectCreationExpression(
SyntaxFactory.SeparatedList <AnonymousObjectMemberDeclaratorSyntax>(keyElements.ToArray()));
}
// this.BuyerKey = new ForeignIndex<Buyer>("BuyerKey").HasIndex(b => b.BuyerId);
return(SyntaxFactory.SimpleLambdaExpression(SyntaxFactory.Parameter(SyntaxFactory.Identifier(abbreviation)), syntaxNode));
}
