Using Caché Objects - InterSystems Documentation

More documents

Recommendations

Info

Class Queries 8.2.2.6 A Note on Method Compilation Order When Studio creates the querynameClose, querynameExecute, and querynameFetch methods, the querynameFetch and querynameClose methods include syntax of the form: [ PlaceAfter = querynameExecute ] The PlaceAfter method keyword ensures proper cursor declaration. The ability to control compilation order is an advanced feature that should be used with caution. InterSystems does not recommend general use of this keyword. 8.2.3 The querynameClose Method The querynameClose method cleans up after data retrieval has finished. Typically, this includes removing variables from memory and closing cursors. The querynameClose method returns status information. Its sole argument is the qHandle variable of type %Binary; this is defined in querynameExecute and is passed by reference. For example, the signature of a ByNameClose method might be: ClassMethod ByNameClose(ByRef qHandle As %Binary) As %Status [ PlaceAfter = ByNameExecute ] { // query cleanup code here } 62 Using Caché Objects
9 Indices Indexes provide a mechanism for optimizing searches across the instances of a persistent class; they define a specific sorted subset of commonly requested data associated with a class. They are very helpful in reducing overhead for performance-critical searches. Indexes automatically span the entire extent of the class in which they are defined. If a Person class has a subclass Student, all indexes defined in Person contain both Person objects and Student objects. Indexes defined in the Student class contain only Student objects. Indexes can be sorted on one or more properties belonging to their class. This allows you a great deal of specific control of the order in which results are returned. (See the Properties keyword, below.) In addition, indexes can store additional data that is frequently requested by queries based on the sorted properties. By including additional data as part of an index, you can greatly enhance the performance of the query that uses the index; when the query uses the index to generate its result set, it can do so without accessing the main data storage facility. (See the Data keyword below.) For additional information on indices, refer to the Index chapter within Using Caché SQL. 9.1 Index Keywords You can modify an index definition through the use of one or more index keywords. Each keyword is optional and has a default value if not explicitly specified. The available index keywords include: Using Caché Objects 63
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 40 and 41: Caché Classes ClientDataType Descr
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: The data in Row is the result of ex
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
Page 91 and 92: There are two types of array proper
Page 93 and 94: Saving Objects 10.5 Saving Objects
Page 95 and 96: mation. Again, this method deletes
Page 97 and 98: Set rset = ##class(%ResultSet).%New
Page 99: Executing Queries // Create a Resul
Page 102 and 103: Data Types 11.1 Available Types Cac
Page 104 and 105: Data Types • INDEXSUBSCRIPTS —
Page 106 and 107: Data Types CLIENTDATATYPE Values Va
Page 108 and 109: Data Types SQLCATEGORY Values Value
Page 110 and 111: Data Types The property is restrict
Page 112 and 113: Object Persistence 1. Its primary (
Page 114 and 115: Object Persistence Note: In a multi
Page 116 and 117: Object Persistence // Open person "
Page 118 and 119: Object Persistence For example: //
Page 120 and 121: Object Persistence If a persistent
Page 122 and 123: Object Persistence The storage clas
Page 125 and 126:
13 Objects and SQL A key aspect of
Page 127 and 128:
The Object-SQL Projection 13.2 The
Page 129 and 130:
The Object-SQL Projection 13.2.2.1
Page 131 and 132:
The Object-SQL Projection • The p
Page 133 and 134:
If the list for a particular instan
Page 135 and 136:
Triggers are, however, fired by the
Page 137 and 138:
14 Relationships A relationship is
Page 139 and 140:
Relationship Basics the relationshi
Page 141 and 142:
An Invoice class class MyApp.Invoic
Page 143:
14.4 Persistent Behavior of Relatio
Page 146 and 147:
Streams Stream data may be stored i
Page 148 and 149:
Streams 15.2.2 Copying Data between
Page 150 and 151:
Streams Set stream=##class(%Stream.
Page 153 and 154:
16 Class Projections Class projecti
Page 155 and 156:
RemoveProjection The RemoveProjecti
Page 157 and 158:
17 Object Synchronization Object sy
Page 159 and 160:
About Updates • If two changes re
Page 161 and 162:
About Updates Two Synchronized Data
Page 163 and 164:
• classname is a quoted string th
Page 165 and 166:
Set Status = TargetSyncSet.Import(f
Page 167 and 168:
18 Method Generators A powerful fea
Page 169 and 170:
Method Generator Context 6. It copi
Page 171:
Implementing Method Generators 3. A
Page 174 and 175:
The Caché Data Population Utility
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Using Callback Methods Since differ
Page 184 and 185:
Using Callback Methods ReturnValue
Page 186 and 187:
Using Callback Methods 20.6 %OnDele
Page 188 and 189:
Using Callback Methods 20.10 %OnRol
Page 191 and 192:
21 Object-Specific ObjectScript Fea
Page 193 and 194:
##this Syntax >Do ##class(Package.C
Page 195 and 196:
##super Syntax 21.4 ##super Syntax
Page 197:
You can override a property's defau
Page 200 and 201:
Dynamic Dispatch 22.2 Content of Me
Page 202 and 203:
Dynamic Dispatch %DispatchMethod ca
Page 205 and 206:
23 Class Definition Classes The Cac
Page 207:
You can get detailed information ab
Page 210 and 211:
Internet Classes addressed to , its
Page 212 and 213:
Internet Classes For more informati
Page 214 and 215:
Object Concurrency Setting 1 2 3 4
Page 216 and 217:
Object Concurrency Note: You can us
show all

Using Caché Objects - InterSystems Documentation

Create successful ePaper yourself

Delete template?

Save as template?