ROW and LIST comparisons

IF ROW(InputBody.Data.*[1],InputBody.Data.*[2]) =
                 ROW('Raf' AS Name,'25' AS Age) THEN ...
IF LIST{InputBody.Data.Name, InputBody.Data.Age} = LIST{'Raf','25'} THEN ...

With the following XML input message body both the IF expressions in both the above statements evaluate to TRUE:

<Data>
   <Name>Raf</Name>
   <Age>25</Age>
</Data>

In the comparison between ROWs, both the name and the value of each element are compared; in the comparison between LISTs only the value of each element is compared. In both cases, the cardinality and sequential order of the LIST or ROW operands being compared must be equal in order for the two operands to be equal. Therefore, the following examples are false because either the sequential order or the cardinality of the operands being compared do not match:

ROW('alpha' AS A, 'beta' AS B) =
             ROW('alpha' AS A, 'beta' AS B, 'delta' AS D)
ROW('alpha' AS A, 'beta' AS B) =
             ROW('beta' AS B,'alpha' AS A)
LIST{1,2,3} = LIST{1,2,3,4}
LIST{3,2,1} = LIST{1,2,3}

Consider the following ESQL:

IF InputBody.Places =
   ROW('Ken' AS first, 'Bob' AS second, 'Kate' AS third) THEN ...

With the following XML input message body, the above IF expression evaluates to TRUE:

<Places>
   <first>Ken</first>
   <second>Bob</second>
   <third>Kate</third>
</Places>

Contrast this with a comparison such as:

IF InputBody.Lottery.FirstDraw = InputBody.Lottery.SecondDraw THEN ...

which compares the value of the FirstDraw and SecondDraw fields, not the names and values of each of FirstDraw and SecondDraw's child fields constructed as a ROW. Thus an XML input message body such as:

<Lottery>
   <FirstDraw>wednesday
      <ball1>32</ball1>
      <ball2>12</ball2>
   </FirstDraw>
   <SecondDraw>saturday
      <ball1>32</ball1>
      <ball2>12</ball2>
   </SecondDraw>
</Lottery>

would not result in the above IF expression being evaluated as TRUE, because the values wednesday and saturday are being compared, not the names and values of the ball fields.

Consider the following ESQL:

IF InputBody.Cities.City[] = LIST{'Athens','Sparta','Thebes'} THEN ...

With the following XML input message body, the IF expression evaluates to TRUE:

<Cities>
	<City>Athens</City>
	<City>Sparta</City>
	<City>Thebes</City>
</Cities>

Two message field arrays can be compared together in this way, for example:

IF InputBody.Cities.Mediaeval.City[] = 
                    InputBody.Cities.Modern.City[] THEN ...

IF InputBody.Cities.Mediaeval.*[] = InputBody.Cities.Modern.*[] THEN ...

IF InputBody.Cities.Mediaeval.(XML.Element)[] = 
                    InputBody.Cities.Modern.(XML.Element)[] THEN ...

With the following XML input message body, the IF expression of the first and third of the statements above evaluates to TRUE:

<Cities>
   <Mediaeval>1350
      <City>London</City>
      <City>Paris</City>
   </Mediaeval>
   <Modern>1990
      <City>London</City>
      <City>Paris</City>
   </Modern>
</Cities>

However the IF expression of the second statement evaluates to FALSE, because the *[] indicates that all the children of Mediaeval and Modern are to be compared, not just the (XML.Element)s. In this case the values 1350 and 1990, which form nameless children of Mediaeval and Modern, are compared as well as the values of the City tags.

The IF expression of the third statement above evaluates to TRUE with an XML input message body such as:

<Cities>
   <Mediaeval>1350
      <Location>London</Location>
      <Location>Paris</Location>
   </Mediaeval>
   <Modern>1990
      <City>London</City>
      <City>Paris</City>
   </Modern>
</Cities>

LISTs are composed of unnamed values. It is the values of the child fields of Mediaeval and Modern that are compared, not their names.