protected static string MakeResultColumnExpression(FieldInfo field, TableOrSubQuery source)
{
var alias = field.Alias;
if (alias != null)
{
return(field.SQLExpression + " AS " + alias);
}
else
{
var sourceName = source.SourceName;
if (string.IsNullOrEmpty(sourceName))
{
return(field.Name);
}
else
{
return(sourceName + "." + field.Name);
}
}
}
public SqlSelectBuilder BuildSelect(TableOrSubQuery source, IFieldInfoCollection fields)
{
if (source is null)
{
throw new ArgumentNullException(nameof(source));
}
if (fields is null)
{
throw new ArgumentNullException(nameof(fields));
}
var selectBuilder = new SqlSelectBuilder();
selectBuilder.Source = source;
foreach (var field in fields)
{
var resultColExpr = MakeResultColumnExpression(field, source);
selectBuilder.ResultColumns.Add(resultColExpr);
}
return(selectBuilder);
}
protected static TableOrSubQuery InitializeSource(Type type)
{
try
{
//read Entity attribute
var eAttr = type.GetCustomAttributes(typeof(TableAttribute), true)
.OfType <TableAttribute>()
.FirstOrDefault();
if (eAttr is null)
{
return(new TableOrSubQuery(type.Name));
}
else
{
var source = new TableOrSubQuery(eAttr.Name);
// to provide backwards compatibility
// check if it is a EntitySourceAttr
#pragma warning disable CS0618 // Type or member is obsolete
if (eAttr is EntitySourceAttribute)
{
var esa = (EntitySourceAttribute)eAttr;
source.Alias = esa.Alias;
source.Joins = esa.JoinCommands;
}
#pragma warning restore CS0618 // Type or member is obsolete
return(source);
}
}
catch (Exception e)
{
throw new ORMException("Unable to initialize EntityDescription for " + type.Name, e);
}
}
//public static QueryBuilder<TResult> From<TResult>(this DbConnection connection, ICommandBuilder commandBuilder = null) where TResult : class, new()
//{
// return From<TResult>(connection, (TableOrSubQuery)null, (ICommandBuilder)null);
//}
public static QueryBuilder <TResult> From <TResult>(this DbConnection connection, TableOrSubQuery source = null, ICommandBuilder commandBuilder = null) where TResult : class, new()
{
commandBuilder = commandBuilder ?? DefaultCommandBuilder;
var discription = GlobalEntityDescriptionLookup.Instance.LookUpEntityByType(typeof(TResult));
SqlSelectBuilder builder = commandBuilder.BuildSelect(source ?? discription.Source, discription.Fields);
return(new QueryBuilder <TResult>(connection, builder));
}
