SQL::Arguments Object - Array

Description

The SQL::Arguments object supports arrays. Here are some examples.

The SQL::Arguments object supports arrays. This is a very powerful addition because it makes support for parameterized SQL queries that contain the IN keyword possible. See example below. To set a SQL::Argument value to an array, you simply create an Xbasic array and then set the argument value to the array, as shown in the following interactive window session.

'create an Xbasic array with 3 elements
dim a[3] as c
a[1] = "Boston"
a[2] = "London"
a[3] = "Berlin"

dim args as sql::arguments 
args.add("whatcity",a)
 
'View the XML property of the SQL::arguments object
?args.xml 
= <SQLArguments>
    <SQLArgument>
        <Name>whatcity</Name>
        <Data Type="C[]">
            <Item Type="C">Boston</Item>
            <Item Type="C">London</Item>
            <Item Type="C">Berlin</Item>
        </Data>
        <IsNull Type="L">0</IsNull>
        <Usage>Input</Usage>
    </SQLArgument>
</SQLArguments>

 
'read the first argument into an Xbasic array
dim aa as p
aa = args[1].data
?aa[1]
= "Boston"
 
'find the data type of the first argument. a type of 'P' indicates that the argument is an array
?typeof(args[1].data)
= "P"
 
 
'find the data type of the array
?typeof(args[1].data[1])
= "C"
 
 
'add a new element to the array.
dim myarr as p
myarr = args[1].data
myarr.push("Santiago")
args[1].data = myarr

In this next example, we show how you can use array arguments in a SQL statement that uses the IN keyword.

dim cities[0] as c
cities.push("London")
cities.push("Madrid")
cities.push("Paris")
 
dim cn as sql::connection
cn.open("::Name::Northwind")
dim sql as c
sql = "select customerId,city from customers where city in (:cities)"
 
dim args as sql::arguments
args.add("cities",cities)
 
?cn.execute(sql,args)
= .t.
?cn.resultset.toString()
= AROUT London
BSBEV London
CONSH London
EASTC London
NORTS London
SEVES London
BOLID Madrid
FISSA Madrid
ROMEY Madrid
PARIS Paris
SPECD Paris