Using Caché Objects - InterSystems Documentation

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Caché Classes ClientDataType Description For a data type class, specifies the type when exposed via ActiveX or Java. There is no default value. Data type classes must specify a client data type. Specifies a description of the class. The description is displayed by the online class documentation system. For an example refer to the description for the %Persistent class. Final Specifies that the class is final; no classes can be derived from it. SQLRowIdName Specifies an alternate field name for the object row ID projected to SQL. By default the row ID is called “ID” . SQLTableName Super Specifies the table name used to identify the class in its SQL projection. By default, Caché uses a class' name as the name of its SQL table. Specifies one or more superclasses for the class (classes that the class extends). By default, classes have no superclasses. For a complete list of class keywords, refer to the Class Definition Reference. 4.3 Class Parameters A class parameter defines a special constant value for all objects of a given class. When you create a class definition (or at any point before compilation), you can set the values for its class parameters. By default, the value of each parameter is the null string; to set a parameter's value, you must explicitly provide a value for it. At compile-time, the value of the parameter is established for all instances of a class. This value cannot be altered at run time. Class parameters are typically used for the following purposes: 28 Using Caché Objects
• To provide parameterized values for method generator methods to use. A method generator is a special type of method whose implementation is actually a short program that is run at compile-time in order to generate the actual runtime code for the method. Many method generators use class parameters as a way of controlling the behavior of method generators. • To customize the behavior of the various data type classes (such as providing validation information). • To define user-specific information about a class definition. A class parameter is simply an arbitrary name/value pair; you can use it to store any information you like about a class. • To define a class-specific constant value. A subclass can define additional class parameters. A subclass can also override the value of an inherited class parameter. For instance, if a class property assigns a value to a data type class parameter, then subclasses of the object's class inherit that property's assigned value. For example, suppose class MyApp.A defines a parameter, XYZ with a value of 10: Class MyApp.A { Parameter XYZ = 100; } A subclass, such as MyApp.B, can override the value of this parameter: Class MyApp.A Extends MyApp.B { Parameter XYZ = 200; } Class parameters have a special behavior when used with data type classes. With data type classes, class parameters are used to provide a way to customize the behavior of the data type. When you define a property within a class, you specify the property's type using a data type class and you can provide specific values for any parameters defined by the data type class. For example, the %Integer data type class has a class parameter, MAXVAL, which specifies the maximum valid value for a property of type %Integer. If you define a class with the property NumKids as follows: Property NumKids As %Integer(MAXVAL=10); Class Parameters This specifies that the MAXVAL parameter for the %Integer class will be set to 10 for the NumKids property. Using Caché Objects 29
Page 1 and 2: Using Caché Objects Version 5.2 01
Page 3 and 4: Table of Contents 1 Introduction to
Page 5 and 6: 7 Properties ......................
Page 7 and 8: 13.1 Inheritance and SQL ..........
Page 9 and 10: 20.8 %OnNew .......................
Page 11 and 12: List of Figures Embeddable Objects
Page 13 and 14: 1 Introduction to Caché Objects Th
Page 15 and 16: 1.2 Class Definitions and the Class
Page 17 and 18: Development Tools Caché Class Libr
Page 19 and 20: • The Caché EJB Binding—a vers
Page 21 and 22: 2 Object-Oriented Database Developm
Page 23 and 24: Encapsulation Caché exploits inher
Page 25 and 26: 3 The Caché Object Model The Cach
Page 27 and 28: Referring to an Object — OREF, OI
Page 29 and 30: Types of Classes 3.2.1 Transient Ob
Page 31 and 32: Types of Classes Embeddable Objects
Page 33 and 34: A class inherits all of the specifi
Page 35: 2. It resolves inheritance—it det
Page 38 and 39: Caché Classes • Class Parameters
Page 42 and 43: Caché Classes Internally, this wor
Page 44 and 45: Packages Class Packages Any of thes
Page 46 and 47: Packages Letting the compiler resol
Page 48 and 49: Packages • “%Library” —any
Page 50 and 51: Methods where count and state are d
Page 52 and 53: Methods 6.4 Method Language You hav
Page 54 and 55: Methods 6.6 Instance and Class Meth
Page 56 and 57: Methods Write dog.Speak() Which cou
Page 58 and 59: Properties 7.1 Property Keywords Yo
Page 60 and 61: Properties Property Behavior The pr
Page 62 and 63: Properties 7.5 Attribute Properties
Page 64 and 65: Properties You can manipulate a col
Page 67 and 68: 8 Class Queries Class queries provi
Page 69 and 70: Query Basics Final Specifies that s
Page 71 and 72: Caché ObjectScript. These queries
Page 73 and 74: The data in Row is the result of ex
Page 75 and 76: 9 Indices Indexes provide a mechani
Page 77 and 78: Index Collation 9.2 Index Collation
Page 79 and 80: 10 Using Objects with Caché Object
Page 81 and 82: Executing Methods 10.1.3 Executing
Page 83 and 84: Opening Objects 10.3 Opening Object
Page 85 and 86: where oref is the OREF of the speci
Page 87 and 88: For example, to populate the Home p
Page 89 and 90: change the second vaccination recor
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There are two types of array proper
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Saving Objects 10.5 Saving Objects
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mation. Again, this method deletes
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Set rset = ##class(%ResultSet).%New
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Executing Queries // Create a Resul
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Data Types 11.1 Available Types Cac
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Data Types • INDEXSUBSCRIPTS —
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Data Types CLIENTDATATYPE Values Va
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Data Types SQLCATEGORY Values Value
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Data Types The property is restrict
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Object Persistence 1. Its primary (
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Object Persistence Note: In a multi
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Object Persistence // Open person "
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Object Persistence For example: //
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Object Persistence If a persistent
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Object Persistence The storage clas
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13 Objects and SQL A key aspect of
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The Object-SQL Projection 13.2 The
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The Object-SQL Projection 13.2.2.1
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The Object-SQL Projection • The p
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If the list for a particular instan
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Triggers are, however, fired by the
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14 Relationships A relationship is
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Relationship Basics the relationshi
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An Invoice class class MyApp.Invoic
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14.4 Persistent Behavior of Relatio
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Streams Stream data may be stored i
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Streams 15.2.2 Copying Data between
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Streams Set stream=##class(%Stream.
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16 Class Projections Class projecti
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RemoveProjection The RemoveProjecti
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17 Object Synchronization Object sy
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About Updates • If two changes re
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About Updates Two Synchronized Data
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• classname is a quoted string th
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Set Status = TargetSyncSet.Import(f
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18 Method Generators A powerful fea
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Method Generator Context 6. It copi
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Implementing Method Generators 3. A
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The Caché Data Population Utility
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Using Callback Methods Since differ
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Using Callback Methods ReturnValue
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Using Callback Methods 20.6 %OnDele
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Using Callback Methods 20.10 %OnRol
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21 Object-Specific ObjectScript Fea
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##this Syntax >Do ##class(Package.C
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##super Syntax 21.4 ##super Syntax
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You can override a property's defau
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Dynamic Dispatch 22.2 Content of Me
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Dynamic Dispatch %DispatchMethod ca
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23 Class Definition Classes The Cac
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You can get detailed information ab
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Internet Classes addressed to , its
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Internet Classes For more informati
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Object Concurrency Setting 1 2 3 4
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Object Concurrency Note: You can us
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