ReadRecord (Dataset function) - Revision history

JAL: /* Usage notes */

2012-11-14T23:41:29Z

Usage notes

← Older revision		Revision as of 23:41, 14 November 2012
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	record to determine if the end of file has been reached.		record to determine if the end of file has been reached.
	</ul>		</ul>

			==Example==
			For a simple example, see [[Dataset class#Dataset example\|"Dataset example"]].

	==See also==		==See also==
	{{Template:Dataset:ReadRecord footer}}		{{Template:Dataset:ReadRecord footer}}

JAL: /* Usage notes */

2012-11-14T23:22:28Z

Usage notes

JAL2 at 22:14, 20 May 2011

2011-05-20T22:14:31Z

← Older revision		Revision as of 22:14, 20 May 2011
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	{{Template:Dataset:ReadRecord subtitle}}		{{Template:Dataset:ReadRecord subtitle}}

	~~This function reads a record of data from an input <var>Dataset</var>.~~
	==Syntax==		==Syntax==
	{{Template:Dataset:ReadRecord syntax}}		{{Template:Dataset:ReadRecord syntax}}
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	<table class="syntaxTable">		<table class="syntaxTable">
	<tr><th>%string</th>		<tr><th>%string</th>
	<td>A string or longstring variable to receive the block of data.		<td>A string or [[Longstrings\|longstring]] variable to receive the block of data.
	</td></tr>		</td></tr>
	<tr><th>%dataset</th>		<tr><th>dataset</th>
	<td>A reference to an instance of a <var>Dataset</var> object.		<td>A reference to an instance of a <var>Dataset</var> object.

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	is exactly equal to the <var>RecordLength</var>.		is exactly equal to the <var>RecordLength</var>.
	<li>For V or VB files, the string returned by <var>ReadRecord</var> has a length less		<li>For V or VB files, the string returned by <var>ReadRecord</var> has a length less
	than the <var>[[RecordLength property\|RecordLength]]</var> property.		than the <var>[[RecordLength (Dataset property)\|RecordLength]]</var> property.
	It does '''not''' contain the record's RDW, that is, it only contains the		It does '''not''' contain the record's RDW, that is, it only contains the
	data portion of the record.		data portion of the record.

DmeWiccan: 1 revision

2011-05-20T18:03:36Z

1 revision

← Older revision	Revision as of 18:03, 20 May 2011
(No difference)

JAL2: Created page with "This function reads a record of data from an input `Dataset`. ==ReadRecord syntax==
%string = %dataset:readRecord
===Syntax terms===
2011-05-20T18:03:34Z
Created page with "This function reads a record of data from an input <var>Dataset</var>. ==ReadRecord syntax== <p class="pre"> %string = %dataset:readRecord </p> ===Syntax terms=== <table class="s..."

← Older revision Revision as of 18:03, 20 May 2011
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{{Template:Dataset:ReadRecord subtitle}}

This function reads a record of data from an input <var>Dataset</var>.
This function reads a record of data from an input <var>Dataset</var>.

==ReadRecord syntax==
==Syntax==

<p class="pre"> %string = %dataset:readRecord
{{Template:Dataset:ReadRecord syntax}}

</p>

===Syntax terms===
===Syntax terms===

<table class="syntaxTable">
<table class="syntaxTable">

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</td></tr></table>
</td></tr></table>

==Usage Notes==
==Usage notes==

<ul>
<ul>

<li>The <var>Dataset</var> object must be an input object, that is, its
<li>The <var>Dataset</var> object must be an input object, that is, its

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record to determine if the end of file has been reached.
record to determine if the end of file has been reached.

</ul>
</ul>

==See also==

{{Template:Dataset:ReadRecord footer}}

JAL2: Created page with "This function reads a record of data from an input `Dataset`. ==ReadRecord syntax==
%string = %dataset:readRecord
===Syntax terms===
2011-05-20T16:47:15Z
Created page with "This function reads a record of data from an input <var>Dataset</var>. ==ReadRecord syntax== <p class="pre"> %string = %dataset:readRecord </p> ===Syntax terms=== <table class="s..."
New page
This function reads a record of data from an input <var>Dataset</var>.
==ReadRecord syntax==
<p class="pre"> %string = %dataset:readRecord
</p>
===Syntax terms===
<table class="syntaxTable">
<tr><th>%string</th>
<td>A string or longstring variable to receive the block of data.
</td></tr>
<tr><th>%dataset</th>
<td>A reference to an instance of a <var>Dataset</var> object.

</td></tr></table>
==Usage Notes==
<ul>
<li>The <var>Dataset</var> object must be an input object, that is, its
<var>[[Output (Dataset property)|Output]]</var> property must be <var>False</var> to use the <var>ReadRecord</var> method.
Using <var>ReadRecord</var> against an output dataset results in request cancellation.
<li>The <var>Dataset</var> object must be in the <var>Open</var> <var>State</var> to use the ReadRecord method.
Using <var>ReadRecord</var> against a dataset in the <var>Closed</var> or <var>AfterEnd</var> state
results in request cancellation.
<li>If a <var>ReadRecord</var> method is used after a <var>ReadBlock</var> method, the first record
in the block after the block returned by the <var>ReadBlock</var> is returned.
<li>For F or FB files, the string returned by <var>ReadRecord</var> has a length that
is exactly equal to the <var>RecordLength</var>.
<li>For V or VB files, the string returned by <var>ReadRecord</var> has a length less
than the <var>[[RecordLength property|RecordLength]]</var> property.
It does '''not''' contain the record's RDW, that is, it only contains the
data portion of the record.
As such, a program that uses <var>ReadRecord</var> can generally be used without
modification (except for, perhaps, record padding issues) for different
<var>RecordFormats</var>.
<li>When a <var>ReadRecord</var> reaches the end of a file, it returns a null string and
switches the dataset to the <var>AfterEnd</var> state.
After this, a <var>ReadRecord</var> or <var>ReadBlock</var> results in request cancellation.
For V or VB datasets, it is possible for <var>ReadRecord</var> to return a null record
when it is not at the end of file.
Because of this, it is probably best to check the <var>Dataset</var>'s
<var>[[State (Dataset property)|State]]</var> property rather than using the size of the returned
record to determine if the end of file has been reached.
</ul>

← Older revision		Revision as of 23:22, 14 November 2012
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	<var>[[Output (Dataset property)\|Output]]</var> property must be <var>False</var> to use the <var>ReadRecord</var> method.		<var>[[Output (Dataset property)\|Output]]</var> property must be <var>False</var> to use the <var>ReadRecord</var> method.
	Using <var>ReadRecord</var> against an output dataset results in request cancellation.		Using <var>ReadRecord</var> against an output dataset results in request cancellation.
	<li>The <var>Dataset</var> object must be in the <var>Open</var> <var>~~State~~</var> ~~to use the ReadRecord~~ method.
			<li>The <var>Dataset</var> object must be in the <var>Open</var> [[Dataset class#The DatasetState enumeration\|state]] to use the <var>ReadRecord</var> method.
	Using <var>ReadRecord</var> against a dataset in the <var>Closed</var> or <var>AfterEnd</var> state		Using <var>ReadRecord</var> against a dataset in the <var>Closed</var> or <var>AfterEnd</var> state
	results in request cancellation.		results in request cancellation.

	<li>If a <var>ReadRecord</var> method is used after a <var>ReadBlock</var> method, the first record		<li>If a <var>ReadRecord</var> method is used after a <var>ReadBlock</var> method, the first record
	in the block after the block returned by the <var>ReadBlock</var> is returned.		in the block after the block returned by the <var>ReadBlock</var> is returned.

	<li>For F or FB files, the string returned by <var>ReadRecord</var> has a length that		<li>For F or FB files, the string returned by <var>ReadRecord</var> has a length that
	is exactly equal to the <var>RecordLength</var>.		is exactly equal to the <var>RecordLength</var>.

	<li>For V or VB files, the string returned by <var>ReadRecord</var> has a length less		<li>For V or VB files, the string returned by <var>ReadRecord</var> has a length less
	than the <var>[[RecordLength (Dataset property)\|RecordLength]]</var> property.		than the <var>[[RecordLength (Dataset property)\|RecordLength]]</var> property value.
	It does '''not''' contain the record's RDW, that is, it only contains the		It does '''not''' contain the record's RDW, that is, it only contains the
	data portion of the record.		data portion of the record.
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	modification (except for, perhaps, record padding issues) for different		modification (except for, perhaps, record padding issues) for different
	<var>RecordFormats</var>.		<var>RecordFormats</var>.

	<li>When a <var>ReadRecord</var> reaches the end of a file, it returns a null string and		<li>When a <var>ReadRecord</var> reaches the end of a file, it returns a null string and
	switches the dataset to the <var>AfterEnd</var> state.		switches the dataset to the <var>AfterEnd</var> state.
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	record to determine if the end of file has been reached.		record to determine if the end of file has been reached.
	</ul>		</ul>

	==See also==		==See also==
	{{Template:Dataset:ReadRecord footer}}		{{Template:Dataset:ReadRecord footer}}