Using Caché Objects - InterSystems Documentation

Class Queries
8.1.3.2 About ROWSPEC
A query's ROWSPEC provides information on the names, data types, headings, and order of
the fields in each row. It is a quoted and comma-separated list of variable names and data
types of the form:
ROWSPEC = "Var1:%Type1,Var2:%Type2[:OptionalDescription]"
The ROWSPEC specifies the order of fields as a comma-separated list. Each field's information
consists of a colon-separated list of its name, its data type (if it is different than the property's
assigned data type), and an optional heading. You can edit a ROWSPEC's code directly, or,
for an existing query, by viewing the query Class Inspector window, expanding the list of
parameters, and using the available dialog box.
The number of elements in the ROWSPEC must match the number of fields in the query.
Otherwise, Caché returns a “Cardinality Mismatch” error.
8.1.3.3 A Class Query Specification Example
The ByName query of the %Sample.Person sample class that comes with Caché has the following
signature:
Query ByName(name As %String = "")
As %SQLQuery(CONTAINID = 1,
ROWSPEC = "ID:%Integer,Name:%String(MAXLEN=30),DOB,SSN",
SELECTMODE = "RUNTIME")
[ SqlName = SP_Sample_By_Name, SqlProc ]
{
SELECT ID, Name, DOB, SSN
FROM Sample.Person
WHERE (Name %STARTSWITH :name)
ORDER BY Name
}
Here, the CONTAINID parameter specifies that the first field is the ID (the default), and the
first field specified in the SELECT statement is, respectively, ID. The ROWSPEC specifies
that the fields are ID (treated as an integer), Name, DOB, and SSN; similarly, the SELECT
statement contains the fields ID, Name, DOB, and SSN, in that order.
8.2 User-Written Class Queries
While simple %SQLQuery queries perform all result set management for you, this is not sufficient
for certain applications. For such situations, Caché allows you to write queries in
58 Using Caché Objects