05fd4Basic Concepts

8/13/2019 05fd4Basic Concepts

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Basic Concepts


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Rapid Application Development Tools

and Technologies

These tools and technologies include:

Cach Studio: An integrated development environment that

supports the object-oriented approach to designing andbuilding applications. With Studio you can define classes usingseveral languages including Cach ObjectScript, Cach Basic,and MVBasic.

Cach Terminal: A command-line interface to the Cachdatabase. The Terminal allows you to open objects to executetheir methods and view their data. You can also execute anumber of commands and access a number of Cach utilitiesincluding the autopopulation utility.


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Zen: A framework for creating dynamic, data intensive, and

richly interactive Web pages. You can create Zen pages usingCach Studio.

The System Management Portal: A browser-based interfacefor system management. Using the portal you can perform

many tasks including defining, viewing, and accessing yourdata in a relational format. You can define your databasetables and query your data using standard SQL.

Cach Studio, Cach Terminal, and the System ManagementPortal, can all be launched from the Cach Cube. Simply clickthe cube and then click a tool on the the menu.


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Cach Cube

The primary Cach interface on Microsoft Windows platforms

is the Cach Cube.

From the Cach Cube, you can start all of the Cach

configuration and management tools.

You can also invoke each Cube command from a shortcut or

command line.

When you click the Cach Cube, a menu appears with

commands to use the Cach utilities and programming

environments.


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Cach Cube

Getting Started Displays links to tutorials, release notes,documentation etc.

Start Cach Starts the default instance specified in the square

brackets after the menu item, for example [CACHE]. If the

Cach server is already started, this option appears dimmed

it is unavailable.

Stop Cach Shuts down or restarts the local Cach instance. If

the Cach server is stopped, this option appears dimmedit

is unavailable.

Studio -Creates, edits, deletes, and compiles Cach class

definitions, CSP (Cach Server Pages) pages, Cach Basic

routines, and Cach ObjectScript routines.

Terminal Invokes the command line interpreter in the Cach

programming environment.


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Cache Cube


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Cach Cube System Management Portal- Performs common system management

tasks. Creates databases and namespaces, and adjusts all Cachconfiguration settings. Displays classes, globals, and routines, andfunctions for managing each. Displays tables and views, perform queriesand SQL management functions.

Documentation-Displays Cach online documentation.

DeepSee-Invokes the InterSystems DeepSee login page. See the Overviewof DeepSeeguide for more information.

Preferred Server [server name] Shows a list of remote servers andmaintains server connections by using the Add/Edit command on the

submenu. The preferred server appears in brackets and has a check marknext to it in the server list.

AboutDisplays Cach version and build information.

Exit Removes the Cach Cube icon from the system tray; this does notstop Cach. elated information
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_prefacehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=DOV_preface


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Namespace It refers to a logical entity that serves as a container for

programs and data.

a namespace allows you to collect objects from multiple

databases into a single frame of reference so that they appear

as if they were all stored together.

Users need only make a simple reference to a global no

matter where it resides

namespace mapping specifies the globalsdatabase location.


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Namespace Name

A namespace name can be up 31 characters long using acombination of letters, numbers, and the characters %, &, and

$.

It must be unique within the dataset (same rules as for a localvariable).

The use of namespace is not case-sensitive, that is, letters can

be uppercase or lowercase.

All namespaces are converted to uppercase internally.


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Creating a Namespace

[Namespaces] Name=a,b,c

Only the first field is required. If the other fields are notspecified, they are set to the system default.

From left to right: a: Default database name for globals.

b: Default database name for routines and classes. Ifthe database is not specified, it defaults to the globals

database. c: Default database name for temporary storage. If the

database is not specified, it defaults to CACHETEMP


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Datasets

A logical entity that represents a directory

name or directory and system name in Cach


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Cach object modelThe Cach object model defines the behavior and features of both

persistent (database) objects as well as transient objects (those notstored). The Cach object model supports the following features:

PersistenceObjects can be stored within the Cach database orin an external database. Stored objects are simultaneouslyprojected as relational tables and can be queried using standard

SQL. The object model is rich enough to define the complete information

required for complex database applications, such as indices, storagestructure, integrity constraints, and so on.

Properties Objects can contain both simple (literal) or object-valued properties. Object-valued properties can be references to

external objects or embedded objects. There are also a variety ofrelationship, collection, and stream properties.

Custom data types Objects can use application-specific datatypes which are themselves defined as classes.


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Methods Objects have behavior associated withthem.

PolymorphismApplications can easily adapt to newcircumstances by providing specializedimplementations of operations. The runtime systemautomatically invokes the correct implementation

based on object type. InheritanceApplications can reuse code by deriving

new components from pre-existing classes.

Each class describes an entity, such as a person, a

record, or an account. An object is a specific instance of a class. An object can

exist on disk, in memory, or in a client application.


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Cach Objects Architecture

The class dictionary A repository of class definitions which isstored within a Cach database. The class dictionary is also used bythe Cach SQL engine and is responsible for maintainingsynchronized object and relational access to Cach data.

The class compiler A set of programs that convert class

definitions into executable code. The object runtime systemA set of features built into the Cach

virtual machine that support object operations (such as objectinstantiation, method invocation, and polymorphism) within arunning program.

The Cach class library A set of prebuilt classes that come withevery Cach installation. This includes classes that are used toprovide behaviors for user-defined classes (such as persistence ordata types) as well as classes that are intended for direct use withinapplications (such as email classes).


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Every Cach namespace contains its own class dictionary whichdefines the available classes for that namespace.

There is a special CACHELIBdatabase, installed as part of Cach,that contains the definitions and executable code for the classes ofthe Cach class library.

These classes are referred to as system classes and all are part ofpackages whose names start with a % character, such as

%Library.Persistent(the names ofmembers of the %Library packagecan be abbreviated, so that %String is an abbreviation for%Library.String).

The class dictionary contains two distinct types of data:

Definition data The actual class definitions that users create. Compilation data Data generated as a result of compiling class

definitions is also stored.

The class dictionary stores its data in a set of globals (persistentarrays) whose names start with ^odd.
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Stringhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistent


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Cach class library

The Cach class library contains a set ofprebuilt classes.

It is automatically installed with every Cach

system within the CACHELIB database. You can view the contents of the Cach class

library using the online class documentation

system provided with Cach. The Cach class library contains a number of

packages, each of which contains a family of

classes.


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Globals

Cach stores its data in multidimensional

sparse arrays, known as globals.

A global is a named multidimensional array

that is stored within a physical Cach

database.

Within an application, the mapping of globals

to physical databases is based on the current

namespace


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There are two types of globals :

An extended global referenceThis is a

global located in a namespace other than the

current namespace.

A process-private globalThis is an array

variable that is only accessible to the process

that created it.
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GGBL_structurehttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_variableshttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_variableshttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_variableshttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_variableshttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GGBL_structure


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The naming conventions for globals are:

A global name begins with a caret character (^) prefix. This

caret distinguishes a global from a local variable. The first character after the caret (^) prefix in a global name

can be: A letter or the percent character (%) .

% globals are typically stored within either the %SYS or

%CACHELIB databases. The other characters of a global name may be letters,

numbers, or the period (.) character. The percent (%)

character cannot be used, except as the first character of a

global name. The period (.) character cannot be used as the

last character of a global name.

A global name may be up to 31 characters long (exclusive of

the caret character prefix). You can specify global names that

are significantly longer, but Cach treats only the first 31

characters as significant.


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Physical Structure of Globals

Globals are stored within physical files using ahighly optimized structure.

Globals are stored on disk within a series of datablocks; the size of each block (typically 8KB) isdetermined when the physical database iscreated.

Cach maintains a sophisticated B-tree-likestructure that uses a set of pointer blocks to link

together related data blocks. Within data blocks, globals are stored

sequentially


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Routines

routine is the unit of execution in a Cach

server.

Routines are portable to all platforms

supported by Cach and automatically

shareable across a Cach environment


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Create a Project

First, create a new project named Phone Book to manage thesource files for the application, as follows:

Start Cach Studio: Right-click the Cach cube and select Studio.

Studio connects to the local Cach server using the namespaceused most recently by Studio (or the USER namespace if this is the

first time Studio is connecting). If Studio is not connected to the namespace in which you want to

work, connect to a different namespace using the File > ChangeNamespace.

By default, Studio displays the Workspace window and creates anew project called Default_system. The Studio Workspace windowindicates the name of the current project as well as the serverconnection and namespace name. The Workspace window shouldbe displayed by default; if you don't see it, display it using the View> Workspace or with the Alt-3 keyboard accelerator.


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To save the new project, use the File > Save

Project As and enter Phone Book.

You can save this project to the Cach server

at any time using the File > Save Project.


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Creating a class

Defining a New Class

You can define this new Person class using Studio's New Classwizard by following these steps:

Start the New Class wizard by selecting File > New > General tab.

Select Cach Class Definition and click OK.

On the first page of the New Class wizard, enter a package name,PhoneBook, a class name, Person, and click Next.

Select Persistent from the list of available class types and clickFinish.

You see a Class Editor window containing the definition of your new

class: Class PhoneBook.Person Extends %Persistent

{

}


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Adding Properties

Add the Name and PhoneNumber properties to thedefinition of the Person class with the New Property wizardas follows:

Select Class > Add > New Property to start the NewProperty wizard.

Enter a name for the new property, Name, and click Finish.

Your class definition includes a property definition:

Class PhoneBook.Person Extends %Persistent [ClassType=Persistent ]

{Property Name As %String;

}


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Add a PhoneNumber property to the class definition in the sameway as you did the Name property by running the New Propertywizard again. You could have also added this new property bycopying, pasting, and modifying the Name property directly into theClass Editor window. Items are indented to structure the code toimprove readability. A plus/minus expansion box is provided to theleft of each item so that you can collapse sections of the code thatyou are not currently looking at.

Class PhoneBook.Person Extends %Persistent [ClassType=Persistent]

{

Property Name As %String;Property PhoneNumber As %String;

}


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Saving and Compiling Your Class

Save this class definition to the database and

compile it into executable code with

Build > Compile or click the Compile icon .

You now have a PhoneBook.Person class

defined in your database.


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Viewing Documentation for Your Class

View the automatically generated documentation for this class inthe Cach online class reference with View > Show ClassDocumentation. To enter descriptions for your class and propertiesso that they appear in the online documentation, you can enterdescriptions above class member declarations using /// (threeslashes) or you can do the following:

Click the Class Inspector and view Class keywords (make the leftcolumn header of the inspector display the word Class)

In the Inspector, double-click the keyword Description.

This opens an editor in which you can enter a description for yourclass, such as the following:

Click OK when you are finished.

Save your class and view the documentation again.


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Introduction to Management PortalThere are four types of users for the portal

Security Manager -View and edit list of users,roles, and other security tasks.

Manager-Change system configuration anddefine backup sets.

Operator- View system status pages andperform backups.

Explorer (public user)- View home page, view

classes, routines, and globals, and use SQL pages,provided the user has access to the appropriateresources

P t l Titl B


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Portal Title Bar

The left side of the title bar displays the following

information: Page name displays the name of the current portal

page

Licensee displays the value of the Customer Name

field in the cache.key file Beneath the InterSystems logo are the following links:

Home brings you to the System Management Portal[Home]page

About displays system overview information

Help opens the online documentation at anappropriate topic
http://localhost:57772/csp/sys/UtilHome.csphttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/sys/UtilHome.csp


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Feedback opens the Feedback page, which allowsyou to report problems or make enhancement requests

specific to the SMP Help opens the online documentation at an

appropriate topic

Logout brings you to the Login page of the portal

The upper right corner of the title bar displays thefollowing information:

Server name the name of the server running Cach

Instance name the name of the Cach instancerunning on the server

User name the name of the user logged into theportal


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functional areas

The portal is divided into three functional

areas:

System AdministrationSystem

administration tasks

Data ManagementDatabase management

tasks

OperationsSystem operation tasks
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portalhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_using_portal


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Introduction to Management Portal

System Administration Menu

Configuration

Security Management

Licencing

Database Encryption

C fi ti


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Configuration

Cach configuration is composed of system

configuration information, namespaces,

databases, operator task configurations,

network connections, and other advanced

settings.


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Memory and Startup Settings

You can choose whether to configure memory

automatically or manually. If you choose Automatically, the system allocates the

amount of memory best suited to Cach given the availablememory.

If you choose Manually, you can specify how global buffer

pool memory is allocated: Memory allocated for Routine Cache (MB) System memory

allocated and used for caching server code.

Memory allocated for 2KB Database Cache (MB) Systemmemory allocated and used for buffering data for legacy 2KBdatabases.

Memory allocated for 8KB Database Cache (MB) Systemmemory allocated and used for buffering data for 8KB databases

See the Memory Configurationsection for details.
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_config


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You can set your Cach instance to start

automatically when the system starts by selecting

the Auto-start on System Boot check box.

If you select the Enable Long Strings check box,

Cach allocates a large string stack to handle long

strings for each process. You can change the Superserver Port Number

(TCP port used to accept incoming client

requests) for this Cach instance. Click Save to save your modifications; restart

Cach to activate them.


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Namespaces

Cach comes with the following predefined

namespaces:

%SYS System management information and

utilities.

DOCBOOK Documentation.

SAMPLES Sample code and applications.

USER Empty at installation. Typically used

for application development


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Perform the following procedures for

configuring namespaces

Create a Namespace

Modify Default Database Mapping

Add Global, Routine, and Package Mapping to

a Namespace

Delete a Namespace
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_config


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Create New Namespace Enter a Name for the namespace.

Do not specify the following reserved system names:BIN, BROKER, DOCBOOK, DOCUMATIC, SYS.

Select an existing database for the default mapping ofthis namespace, or click Create New Database

Select the Create a default CSP application for thisnamespace check box if you are creating a CSPapplication that accesses this namespace.

You can also Copy namespace mappings from anexisting namespace.

After entering the required information, click Save toadd your namespace to the configuration


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Modify Default Database Mapping You can change the database to which your

namespace is mapped without restarting Cach: Navigate to the [Home] > [Configuration] >

[Namespaces]page to see a list of definednamespaces.

Click Edit in the row of the namespace you wishto modify.

Choose the Default Database for Globals, the

Default Database for Routines, and the DefaultDatabase for Temporary Storage from the list ofdefined databases.

Click Save
http://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csp


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In addition to having access to the globals and routinesin the mapped database, you can also map globals,routines, and class packages from other databases onthe same or different systems. This allows simplereferences to data which can exist anywhere and is theprimary feature of a namespace.

Click the appropriate choice to begin mapping:

Global Mappings

Routine Mappings

Package Mappings

Mapping Data to All Namespaces
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_confighttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSA_config


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Sample Namespace Mapping

Data and programs are stored in Cach

databases, the physical storage locations, and

referred to by namespaces, the logical

references.


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Delete a Namespace

You can delete a namespace, including allmappings associated with it:

Navigate to the [Home] > [Configuration] >

[Namespaces]page, and click Delete in the row ofthe namespace you want to delete.

On the Delete Namespaces page, if you want todelete the CSP pages from the physical path,

select the check box. To delete the namespace and associated

mappings, click Perform Action Now.
http://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csphttp://localhost:57772/csp/sys/mgr/UtilSysNamespaces.csp


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Configuring Databases

A database is a cache.dat file you create using the Database

Wizard. A Cach database holds data in multidimensional arrays

called globals and executable content called routines, aswell as class and table definitions.

Globals and routines encompass such things as methods,

classes, Web pages (CSP and HTML), SQL, BASIC, andJavaScript files.

Cach databases dynamically expand as needed, thoughyou can set a maximum limit.

Cach automatically mounts the databases, which can grow

to be 32 terabytes. Cach provides wizards for both local and remote database

creation


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Journal

Each instance of Cach keeps a journal.

The journal is a set of files that keeps a time-sequenced log of changes that have been

made to the databases since the last backup. Cach transaction processingworks with

journaling to maintain the logical integrity ofdata.

Backups and journaling are daily operationsthat allow you to recreate your database
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_tphttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GCOS_tp


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Class Type

Class MyApp.MyClass [ClassType = persistent] {}

datatype the class is a datatype class used to represent a literalvalue.

persistent the class represents data to be stored within the

database. serial the class represents data to be stored (in its serialized

state) within another persistent object.

stream the class represents streaming data.

view the class is used to define an SQL view (see the ViewQuery

keyword). An empty string, which indicates that this class has no specific type.

Simple registered objects as well as abstract classes typically do notspecify a class type.
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=ROBJ_class_viewqueryhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=ROBJ_class_viewquery


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Specifies how this class is to be used. The class

compiler uses the ClassType keyword to

determine how to compile a class. For

example, if ClassType is persistent, the classcompiler additionally invokes the storage

compiler to generate persistence code for a

class. Unless explicitly defined, the value ofClassType is either the default value (NULL) or

it is inherited from the primary superclass.


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Types of Classes

Classes are divided into data type classes and

object classes.

Data type classes represent literal values such

as strings, integers, and dates

Data type classes are used to create literal

properties of other objects. They do not have

properties and cannot be instantiated


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Object classes

Object classes may have properties and can be

instantiated.

Object classes are further divided, according

to their database behavior, into transientobjects, persistent objects, and serial objects.

A transient object (derived directly from the

%RegisteredObjectclass) has no storagebehavior; it exists only in memory.
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObject


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Instantiations of classes derived from

%RegisteredObjectare known as registered or

transient objects.

These objects have a full set of built-inmethods for controlling their in-memory

behavior.

P i t t Obj t Cl
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.RegisteredObject


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Persistent Object Classes

Instantiations of classes derived from %Persistentareknown as persistent objects

these objects are registered objects that inherit fromthe %Persistentclass.

Persistent objects have the ability to store themselvesinto the database.

lazy loading : Loading a persistent object into memoryfrom the database does not load any other objects that

it refers to. As soon as a referenced object is referredto, however, it is automatically brought into memory;this is known as swizzlingor lazy loading .
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistenthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Persistent


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Serial Object Classes

Instantiations of classes derived from%SerialObjectare known as serial orembeddableobjects

these objects are registered objects thatinherit from the %SerialObjectclass.

These objects can exist independently inmemory, but, when stored to the database,can only exist as embedded within a persistentobject.
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObjecthttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.SerialObject


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Embedded objects

Embedded objects have different in-memory and on-disk representations.

In memory, an embedded object is represented as aseparate object. The in-memory value of an embedded

object attribute is an OREF that refers to the objectsin-memory representation.

On disk, an embedded object property is stored as partof its containing object. A serial object has no separateidentity (OID) and cannot be referred to by other

objects. The values of the embedded objectsproperties are serialized and stored along with all ofthe other object attributes.


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Address class

Class MyApp.Address Extends %SerialObject

{

Property Street As %String(MAXLEN=80); Property

City As %String(MINLEN=3);Property State As %String(MINLEN=2);

}

Once defined, the Address class can be used as anembedded object attribute for a persistent objectclass such as Patient:


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Class MyApp.Patient Extends %Persistent

{

Property Name As %String;

Property Home As Address;

}

D t T Cl


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Data Type Classes

Data type classes define and control literal values. Unlike object classes, data types do not have any

independent identity and can never be explicitly

instantiated.

Instead, they exist only as properties of the

objects that contain them.

Data type classes cannot contain properties.

A data type is a class with its ClassType keyword

set to datatype.

Class Type Page


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Class Type Page

The New Class wizard asks you what type of class you

would like to create. You can either extend (inheritfrom) a previously defined class or create a new classby selecting one of the following options:

Persistent- Create a definition for a persistent class.Persistent objects can be stored in the database.

Serial-Create a definition for a serial class. Serialobjects can be embedded in persistent objects tocreate complex data types such as addresses.

Registered-Create a definition for a registered class.

Registered objects are not stored in the database. Abstract-Create a definition for an abstract class with

no superclass.


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Datatype-Create a definition for a data type class.A data type class is used to create user-defined

data types. CSP(used to process HTTP events)-Create a

definition for a %CSP.Pageclass. A CSP class isused to create a CSP event handling class. This is

a programmatic way to create CSP Pages or torespond to HTTP events (for example, to createan XML server).

Extends-Extend an existing class: check Extendsand enter (or choose from a list) the name of anexisting superclass.

If you are creating a new persistent or serial class the New
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%CSP.Pagehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%CSP.Pagehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%CSP.Page


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If you are creating a new persistent or serial class, the NewClass wizard prompts for certain items particular topersistent or serial classes. These include:

Owner- (optional) For a persistent class, enter the SQL user

name to be the owner of the new class. This user namecontrols privileges when this class is used via SQL. If thisfield is left blank, then the default owner, _system, is used.

SQL Table Name-(optional) For a persistent class, enter aname to be used for the SQL table that corresponds to this

class. If this field is left blank, then the SQL table name isidentical to the class name. If the class name is not a validSQL identifier, you must enter an SQL table name here.

XML Enabled-(optional) If selected, the class is XML-enabled; that is, it has the ability to project itself as an XML

document. It can also be used in Web Service methods.This is equivalent to adding the %XML.Adaptorclass to theclass' superclass list.
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%XML.Adaptorhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%XML.Adaptorhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%XML.Adaptorhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%XML.Adaptor


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Zen DataModel-(optional) If checked, the classincludes extends %ZEN.DataModel.Adaptor.

Data Population-(optional) If you select this option,your new class supports automatic data population.This is equivalent to adding the %Library.Populateclass

to the class' superclass list. Automatic data population allows you to easily create

random data with which you can test the operation ofyour class. To populate a class, compile it and then

execute the class' Populate method (inherited from the%Library.Populateclass). For example, using the Cachterminal:Do ##class(MyApp.Person).Populate(100)
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populatehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populatehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populatehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populatehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populatehttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%Library.Populate


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If you are creating a new CSP class, the New

Class wizard prompts for the following value:

Content Type-Specifies what the content type

served by this CSP class is. The availableoptions are HTML or XML. This option is used

to set the value of the CONTENTTYPE

parameter of the new class to text/html ortext/xml respectively.

Adding Properties to a Class


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Adding Properties to a Class

You can add a new property to a class in two

ways:

Adding the property to the class definition in

the Class Editor.

Using the New Property wizard


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Using Class Editor

position the cursor on a blank line in the Class

Editor and enter a property declaration:

Class MyApp.Person Extends %Persistent

[ClassType = persistent]

{

Property Name As %String;

Property Title As %String;

}

Using New Property Wizard


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Using New Property Wizard

To open the New Property wizard, select Class> Add > New Property . Alternatively, right-click the Class Inspector and select Add > NewProperty or, if only properties are displayed

(Property heads the left column), right-clickand select New Property or select the NewProperty icon, from the toolbar.

Students task: Explore Adding properties to aclass


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Class Compilation

Cach class definitions are compiled into applicationroutines by the Cach class compiler.

Classes cannot be used in an application before theyare compiled.

The Cach class compiler differs from the compilersavailable with other programming languages, such asC++ or Java, in two significant ways:

first, the results of compilation are placed into a shared

repository (database), not a file system. Second, it automatically provides support for

persistent classes.


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class compiler does the following: It generates a list of dependencies Depending on the compile options

used, any dependencies that have been modified since last beingcompiled will also be compiled.

It resolves inheritance it determines which methods, properties, andother class members are inherited from superclasses. It stores thisinheritance information into the class dictionary for later reference.

For persistent and serial classes, it determines the storage structureneeded to store objects in the database and creates the necessaryruntime information needed for the SQL representation of the class.

It executes any method generatorsdefined (or inherited) by the class.

It creates one or more routines that contain the runtime code for theclass. The class compiler groups methods according to language (CachObjectScript and Basic) and generates separate routines, each containingmethods of one language or the other.

It compiles all of the generated routines into executable code.

It creates a class descriptor. This is a special data structure (stored as aroutine) that contains all the runtime dispatch information needed tosupport a class (names of properties, locations of methods, and so on).
http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GOBJ_methodgenhttp://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GOBJ_methodgen


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Class Compilation

several ways to invoke the class compiler:

From within Cach Studio using the option in

the Build menu.

From the Cach command line (in the Cach

Terminal) using the Compile method of the

%SYSTEM.OBJobject:

Do $System.OBJ.Compile("MyApp.MyClass")

Unified Data Architecture
http://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%SYSTEM.OBJhttp://localhost:57772/csp/documatic/%CSP.Documatic.cls?APP=1&LIBRARY=%SYS&CLASSNAME=%SYSTEM.OBJ


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This table summarizes the mapping between the basic

object-oriented features of Cach Objects and therelational features of SQL Tables.

Unified Data Architecture

Cach Objects SQL Tables

Package Schema Class Table

Object Instance Table Row

Property Table Column

Method Stored Procedure Relationship Foreign Key

Embedded Object Column Subset

Date post:	04-Jun-2018
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05fd4Basic Concepts

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