private static void VisitBinary(BinaryExpression node, SQLQueryPredicate predicate)
{
var parameterName = node.Left.NodeType == ExpressionType.Convert ? VisitMember(((UnaryExpression)node.Left).Operand as MemberExpression).ToString()
: VisitMember(node.Left as MemberExpression).ToString();
predicate.ParameterSQLName = SqlMapperExtensions.EncaseWithSquareBrackets(parameterName);
switch (node.Right.NodeType)
{
case ExpressionType.Convert:
predicate.ParameterSQLValue = VisitMember((node.Right as UnaryExpression).Operand as MemberExpression);
break;
case ExpressionType.Constant:
predicate.ParameterSQLValue = VisitConstant(node.Right as ConstantExpression);
break;
case ExpressionType.MemberAccess:
predicate.ParameterSQLValue = VisitMember(node.Right as MemberExpression);
break;
default:
throw new NotSupportedException($"The query expression type {node.Right.NodeType} is not supported");
}
predicate.ParameterArgumentSQLName = parameterName;
}
public IEnumerable <TData> Select <TData>(IDbConnection connection, Expression <Func <TData, bool> > predicate)
{
if (connection.State != ConnectionState.Open)
{
connection.Open();
}
var name = SqlMapperExtensions.GetTableName(typeof(TData));
var query = SQLExpressionVisitor.GetQuery(predicate);
// this no-locks by default... Something to be aware of if ever we need to read only committed data
var sql = "select * from " + SqlMapperExtensions.EncaseWithSquareBrackets(name) + " with (nolock) where " + query.GetParameterizedSQLString();
return(ExecuteSQLQuery <TData>(connection, sql, query.GetParameterizedSQLArgs()));
}
public static SQLQueryPredicate Build(Expression expression)
{
var result = new SQLQueryPredicate {
SourceExpression = expression
};
string parameterName;
switch (expression.NodeType)
{
case ExpressionType.GreaterThanOrEqual:
result.SQLOperator = ">=";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.LessThanOrEqual:
result.SQLOperator = "<=";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.LessThan:
result.SQLOperator = "<";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.GreaterThan:
result.SQLOperator = ">";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.Equal:
result.SQLOperator = "=";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.Not:
return(Build(Expression.Equal(((UnaryExpression)expression).Operand, Expression.Constant(false))));
case ExpressionType.NotEqual:
result.SQLOperator = "<>";
VisitBinary(expression as BinaryExpression, result);
break;
case ExpressionType.Lambda:
return(Build((expression as LambdaExpression).Body));
case ExpressionType.Convert:
return(Build((expression as UnaryExpression).Operand));
case ExpressionType.Constant:
parameterName = VisitMember(expression as MemberExpression).ToString();
result.ParameterSQLName = SqlMapperExtensions.EncaseWithSquareBrackets(parameterName);
result.ParameterSQLValue = VisitConstant(expression as ConstantExpression);
result.ParameterArgumentSQLName = parameterName;
break;
case ExpressionType.MemberAccess:
parameterName = VisitMember(expression as MemberExpression).ToString();
result.ParameterSQLName = SqlMapperExtensions.EncaseWithSquareBrackets(parameterName);
PropertyInfo boolMemberAccess;
if (TryCheckForMemberAccessBoolExpression(expression, out boolMemberAccess))
{
result.SQLOperator = "=";
result.ParameterSQLValue = true;
}
else
{
// ???
throw new NotImplementedException();
}
result.ParameterArgumentSQLName = parameterName;
break;
default:
throw new NotSupportedException($"The query expression type {expression.NodeType} is not supported");
}
return(result);
}
