Domain Driven Design: The Good Parts
The greenfield project started out so promising. Instead of devolving into big ball of mud, the team decided to apply domain-driven design principles. Ubiquitous language, proper boundaries, encapsulation, it all made sense.
But along the way, something went completely and utterly wrong. It started with arguments on the proper way of implementing aggregates and entities. Arguments began over project and folder structure. Someone read a blog post that repositories are evil, and ORMs the devil incarnate. Another read that relational databases are last century, we need to store everything as a stream of events. Then came the actor model and frameworks that sounded like someone clearing their throat. Instead of a nice, clean architecture, the team chased the next new approach without ever actually shipping anything.
Beyond the endless technical arguments it causes, domain-driven design can actually produce great software. We have to look past the hype into the true value of DDD, what it can bring to our organizations and how it can enable us to build quality systems. With the advent of microservices, DDD is more important than ever - but only if we can get to the good parts.
Microcharts is an extremely simple charting library for a wide range of platforms (see Compatibility section below), with shared code and rendering for all of them!
DECLARE @data XML SET @data = '<people> <person> <name> <givenName>name1</givenName> <familyName>lname1</familyName> </name> <age>33</age> <height>short</height> </person> <person> <name> <givenName>name2</givenName> <familyName>lname2</familyName> </name> <age>40</age> <height>short</height> </person> <person> <name> <givenName>name3</givenName> <familyName>lname3</familyName> </name> <age>30</age> <height>medium</height> </person> </people>'
declare @data xml set @data = (select * from openrowset(bulk 'c:\path\data.xml', single_blob) as x)
for $p in doc("data.xml")/people/person
where $p/age > 30
return $p/name/givenName/text() SELECT @data.query('
for $p in /people/person
where $p/age > 30
return $p/name/givenName/text()
') SELECT @data.value('/people/person/age', 'int') XQuery [value()]: 'value()' requires a singleton (or empty sequence), found operand of type 'xdt:untypedAtomic *'
SELECT @data.value('(/people/person/age)[1]', 'int') Infer.exe people.xml -o schema.xsd
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="people">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" name="person">
<xs:complexType>
<xs:sequence>
<xs:element name="name">
<xs:complexType>
<xs:sequence>
<xs:element name="givenName" type="xs:string" />
<xs:element name="familyName" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="age" type="xs:unsignedByte" />
<xs:element name="height" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema> declare @schema xml set @schema = (select * from openrowset(bulk 'c:\path\schema_1.xsd', single_blob) as x)
CREATE XML SCHEMA COLLECTION poeple_xsd AS @schema
DECLARE @data XML(poeple_xsd) SET @data = 'مانند قبل با همان محتوایی که در ابتدای بحث عنوان شد'
SELECT @data.value('/people/person[1]/age', 'int') XQuery [value()]: 'value()' requires a singleton (or empty sequence), found operand of type 'xs:unsignedByte *'
DECLARE @data XML(document poeple_xsd)
DECLARE @x XML SET @x='' SELECT @x.query( ' 1,2 (: 1,2 :) ')
DECLARE @x XML SET @x='' SELECT @x.query( ' for $x in (1,2,3) for $y in (4,5) return ($x,$y) ')
DECLARE @x XML SET @x='' SELECT @x.query( ' 1, <node/> ')
XQuery [query()]: Heterogeneous sequences are not allowed: found 'xs:integer' and 'element(node,xdt:untyped)'
Looking Ahead to C# 7 with Mads Torgersen
