Recordset class - Revision history

JAL: remove excessive blanks from paste of example

2015-10-05T20:05:52Z

remove excessive blanks from paste of example

← Older revision		Revision as of 20:05, 5 October 2015
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	The <var>LoopLockStrength</var> property indicates the minimum lock strength for		The <var>LoopLockStrength</var> property indicates the minimum lock strength for
	the record being processed in an iteration of a loop (<var>For Each Record</var> or		the record being processed in an iteration of a loop (<var>For Each Record</var> or
	<var>For ~~<~~n> Records</var>) on a <var>Recordset</var> object.		<var>For <i>n</i> Records</var>) on a <var>Recordset</var> object.
	If the <var>LoopLockStrength</var> is the same as or weaker than the <var>LockStrength</var>		If the <var>LoopLockStrength</var> is the same as or weaker than the <var>LockStrength</var>
	of a <var>Recordset</var> object, no action is required at each iteration of a		of a <var>Recordset</var> object, no action is required at each iteration of a
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	====Counting====		====Counting====
	Many statements that can be used with traditional, labeled found sets		Many statements that can be used with traditional, labeled found sets
	are not supported for <var>Recordset</var> objects (see [[#Unsupported statement contexts\|"Unsupported statement contexts"]]).		are not supported for <var>Recordset</var> objects (see [[#Unsupported statement contexts\|Unsupported statement contexts]]).
	Although the <var>Count Records</var> statement is ''not'' supported for objects,		Although the <var>Count Records</var> statement is ''not'' supported for objects,
	it has a replacement: the <var>Count</var> method.		it has a replacement: the <var>Count</var> method.
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	These include:		These include:
	<ul>		<ul>
	<li><var>Count Records In</var> (but see [[#Counting\|"Counting"]])		<li><var>Count Records In</var> (but see [[#Counting\|Counting]])
	<li><var>Delete Records In</var>		<li><var>Delete Records In</var>
	<li><var>File Records In</var>		<li><var>File Records In</var>
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	</p>		</p>

			===Example: Counting rectypes===
			This example illustrates the power of <var>Recordset</var> objects compared to record lists. The following utility is one that many people have written, and the logic is often difficult to follow when lists are employed. <var>Recordset</var> objects are a very efficient way to investigate a record structure and report on a file's record structure. As the code shows, the logic being performed is also very easy to understand:

	=~~==Example: Counting rectypes===~~		<p class="code">begin
	~~This example illustrates the power of <var~~>Recordsets</var> over record lists. The following utility is one that many people have written, and the logic is often difficult to follow when lists are employed. <var>Recordsets</var> are a very efficient way to investigate a record structure and report on a file's record structure. As the code shows, the logic being performed is also very easy to understand.

	~~<p class="code">begin~~

	%master is object recordset in file vendors		%master is object recordset in file vendors
	%final is object recordset in file vendor		%final is object recordset in file vendor
	%interim is object recordset in file vendor		%interim is object recordset in file vendor
	%rectype is string len 64		%rectype is string len 64
	%recTracker is namedArrayList of float		%recTracker is namedArrayList of float

	%final = New		%final = New
	%recTracker = New		%recTracker = New

	find all records to %master		find all records to %master
	end find		end find

	for each record in %master		for each record in %master
	%rectype = rectype		%rectype = rectype

	~~%final:addRecord(currentRecord)~~
	~~find all records in %master to %interim~~
	~~rectype = %rectype~~
	~~end find~~
	~~%recTracker(%rectype) = %interim:Count~~
	~~%master:removeRecordset(%interim)~~
	~~end for~~

	~~%recTracker:print~~

	~~end~~

			%final:addRecord(currentRecord)
			find all records in %master to %interim
			rectype = %rectype
			end find
			%recTracker(%rectype) = %interim:Count
			%master:removeRecordset(%interim)
			end for

			%recTracker:print

			end
	</p>		</p>

Alan at 16:37, 28 September 2015

2015-09-28T16:37:41Z

@@ Line 433: / Line 433: @@
 release all records
 end
 </p>

DCameron: /* Using Recordset objects */

2015-04-13T12:37:39Z

Using Recordset objects

← Older revision		Revision as of 12:37, 13 April 2015
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	</p>		</p>

	The flexibility of <var>Recordset</var> objects also allows the same <var>Recordset</var>		The flexibility of <var>Recordset</var> objects also allows the same <var>Recordset</var> to have different lock strengths for the same <var>For</var> loop:
	to have different lock strengths for the same <var>For</var> loop:
	<p class="code"> %order is object recordSet in file orders		<p class="code"> %order is object recordSet in file orders

DCameron at 12:34, 13 April 2015

2015-04-13T12:34:46Z

← Older revision		Revision as of 12:34, 13 April 2015
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	Because the same <var>Recordset</var> object can be used as the target of any		Because the same <var>Recordset</var> object can be used as the target of any
	number of <var>Find</var> statements, you can forego one of the		number of <var>Find</var> statements, you can forego one of the
	most common uses of Lists in User Language: holding the results of alternate		most common uses of Lists in User Language: holding the results of alternate <var>Find</var> criteria.
	<var>Find</var> criteria.

	For example, here is a case where a lookup		For example, here is a case where a lookup

JAL: minor cleanup

2014-11-11T23:01:57Z

minor cleanup

← Older revision		Revision as of 23:01, 11 November 2014
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	<p class="code"> %custList is object recordSet in group customer		<p class="code"> %custList is object recordSet in group customer

	if %id ne '' then		if %id ne '' then
	find records to %custList		find records to %custList
	id eq %id		id eq %id
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	==List of Recordset methods==		==List of Recordset methods==
	The [[List of Recordset methods~~\|"List of Recordset methods"~~]] shows all the class methods.		The [[List of Recordset methods]] shows all the class methods.

	[[Category:System classes]]		[[Category:System classes]]

JAL: /* Find statement formats */

2014-06-30T20:26:29Z

Find statement formats

← Older revision		Revision as of 20:26, 30 June 2014
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	In Group Accounts Fdwol '''To %recordSet''' field Is Present		In Group Accounts Fdwol '''To %recordSet''' field Is Present
	</p>		</p>
	<blockquote class="note"><b>Note:</b>		<blockquote class="note">
	As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies		<p><b>Note:</b>
	the file or group context to which the <var>Find</var> statements apply.		As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies the file or group context to which the <var>Find</var> statements apply.
	The <var>In File</var> and <var>In Group</var> clauses in the statements above '''must'''		The <var>In File</var> and <var>In Group</var> clauses in the statements above '''must'''
	agree with their corresponding object declarations.		agree with their corresponding object declarations.
	For an example where an <var>In Group</var> clause is more meaningful,		For an example where an <var>In Group</var> clause is more meaningful,
	see [[#Selecting group members\|"Selecting group members"]].		see [[#Selecting group members\|"Selecting group members"]]. </p>
	<p>		<p>
	If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.</p>		If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.</p>

Admin at 00:19, 29 June 2013

2013-06-29T00:19:10Z

JAL: /* Find statement formats */

2013-06-26T22:12:24Z

Find statement formats

← Older revision		Revision as of 22:12, 26 June 2013
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	In Group Accounts Fdwol '''To %recordSet''' field Is Present		In Group Accounts Fdwol '''To %recordSet''' field Is Present
	</p>		</p>
	<p class="note"><b>Note:</b>		<div class="note"><b>Note:</b>
	As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies		As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies
	the file or group context to which the <var>Find</var> statements apply.		the file or group context to which the <var>Find</var> statements apply.
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	For an example where an <var>In Group</var> clause is more meaningful,		For an example where an <var>In Group</var> clause is more meaningful,
	see [[#Selecting group members\|"Selecting group members"]].		see [[#Selecting group members\|"Selecting group members"]].
	~~</p>~~

	If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.		If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.
			</div>

	===Locking for Recordset objects===		===Locking for Recordset objects===

JAL: /* Find statement formats */

2013-06-26T21:45:05Z

Find statement formats

← Older revision		Revision as of 21:45, 26 June 2013
Line 92:		Line 92:
	For an example where an <var>In Group</var> clause is more meaningful,		For an example where an <var>In Group</var> clause is more meaningful,
	see [[#Selecting group members\|"Selecting group members"]].		see [[#Selecting group members\|"Selecting group members"]].
			</p>

	If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.		If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.

	===Locking for Recordset objects===		===Locking for Recordset objects===
	<var>Find</var> statements that create a <var>Recordset</var> object also determine		<var>Find</var> statements that create a <var>Recordset</var> object also determine

JAL: /* Creating Recordset objects */

2013-06-26T21:40:31Z

Creating Recordset objects

← Older revision		Revision as of 21:40, 26 June 2013
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	variable <code>%recset</code> and the <var>Recordset</var> method <code>Copy</code>		variable <code>%recset</code> and the <var>Recordset</var> method <code>Copy</code>
	(or any system or user class method or class variable) is '''not''' allowed.		(or any system or user class method or class variable) is '''not''' allowed.
			</p>

	===Find statement formats===		===Find statement formats===

← Older revision		Revision as of 00:19, 29 June 2013
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	In Group Accounts Fdwol '''To %recordSet''' field Is Present		In Group Accounts Fdwol '''To %recordSet''' field Is Present
	</p>		</p>
	<~~div~~ class="note"><b>Note:</b>		<blockquote class="note"><b>Note:</b>
	As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies		As shown in the [[#infind\|introductory example]], the <var>Recordset</var> object declaration specifies
	the file or group context to which the <var>Find</var> statements apply.		the file or group context to which the <var>Find</var> statements apply.
Line 92:		Line 92:
	For an example where an <var>In Group</var> clause is more meaningful,		For an example where an <var>In Group</var> clause is more meaningful,
	see [[#Selecting group members\|"Selecting group members"]].		see [[#Selecting group members\|"Selecting group members"]].
			<p>
	If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.		If there is no <var>In File</var> or <var>In Group</var> clause, there must be a default file context.</p>
	</~~div~~>		</blockquote>

	===Locking for Recordset objects===		===Locking for Recordset objects===
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	The following statements instantiate <var>Recordset</var> objects with		The following statements instantiate <var>Recordset</var> objects with
	locking level <var>None</var>, then with level <var>Share</var>, then with level <var>Exclusive</var>.		locking level <var>None</var>, then with level <var>Share</var>, then with level <var>Exclusive</var>.
	<p class="code">find without locks records to %recordSet		<p class="code">find without locks records to %recordSet
	...		...
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	presents the possibility that a <var>For Each Record</var> loop might be		presents the possibility that a <var>For Each Record</var> loop might be
	executed with different lock strengths in different situations.		executed with different lock strengths in different situations.

	===Supported statement contexts===		===Supported statement contexts===
	A <var>Recordset</var> object can be used in relatively few contexts:		A <var>Recordset</var> object can be used in relatively few contexts:
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	<p class="code"> find records in label to %recordSet		<p class="code"> find records in label to %recordSet
	</p>		</p>

	<li><var>For Each Record</var> statement		<li><var>For Each Record</var> statement

	<li><var>Release Records</var> statement		<li><var>Release Records</var> statement

	<li><var>Sort Records</var> statement		<li><var>Sort Records</var> statement

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	The following subsection has more detail on <var>Sort</var>.		The following subsection has more detail on <var>Sort</var>.
	</ul>		</ul>

	====Sorting====		====Sorting====
	While you can reference a sort label, as shown above, to work with the output of a sort operation on a <var>Recordset</var> object, it's generally more useful to use a [[SortedRecordset class]] object as the target of a sort.		While you can reference a sort label, as shown above, to work with the output of a sort operation on a <var>Recordset</var> object, it's generally more useful to use a [[SortedRecordset class]] object as the target of a sort.