using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data.Common; using Marr.Data.QGen.Dialects; using System.Linq.Expressions; namespace Marr.Data.QGen { /// <summary> /// This class overrides the WhereBuilder which utilizes the ExpressionVisitor base class, /// and it is responsible for translating the lambda expression into a "JOIN ON" clause. /// It populates the protected string builder, which outputs the "JOIN ON" clause when the ToString method is called. /// </summary> /// <typeparam name="T">The entity that is on the left side of the join.</typeparam> /// <typeparam name="T2">The entity that is on the right side of the join.</typeparam> public class JoinBuilder<T, T2> : WhereBuilder<T> { public JoinBuilder(DbCommand command, Dialect dialect, Expression<Func<T, T2, bool>> filter, TableCollection tables) : base(command, dialect, filter.Body, tables, false, true) { } protected override string PrefixText { get { return "ON"; } } protected override Expression VisitMemberAccess(MemberExpression expression) { string fqColumn = GetFullyQualifiedColumnName(expression.Member, expression.Expression.Type); _sb.Append(fqColumn); return expression; } } }