Reread - Revision history

Laura: /* Syntax */

2014-05-05T17:26:47Z

Syntax

← Older revision		Revision as of 17:26, 5 May 2014
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	===Syntax===		===Syntax===
	REREAD #<file number> [, USING {<string expression>\|<line ref>}] [, {RESERVE\|RELEASE}] : [{Mat <array name>\|<variable name>}][,...] [<error condition> <line ref>][,...]		REREAD #<[[file number]]> [, [[USING]] {<[[string expression]]>\|<[[line ref]]>}] [, {[[RESERVE]]\|[[RELEASE]]}] : [{[[Mat]] <[[array name]]>\|<[[variable name]]>}][,...] [<[[error condition]]> <[[line ref]]>][,...]

	[[Image:Reread.png\|900px]]		[[Image:Reread.png\|900px]]

Laura: /* Syntax */

2014-04-29T14:18:01Z

Syntax

← Older revision		Revision as of 14:18, 29 April 2014
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	===Syntax===		===Syntax===
			REREAD #<file number> [, USING {<string expression>\|<line ref>}] [, {RESERVE\|RELEASE}] : [{Mat <array name>\|<variable name>}][,...] [<error condition> <line ref>][,...]

	[[Image:Reread.png\|900px]]		[[Image:Reread.png\|900px]]

Laura: /* Comments and Examples */

2013-05-18T16:37:07Z

Comments and Examples

← Older revision		Revision as of 16:37, 18 May 2013
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	===Comments and Examples===		===Comments and Examples===
	An internal or external file must already be opened and assigned a file number before REREAD can be used. REREAD must follow a successful [[READ]] or REREAD. Although REREAD can be used with [[SEQUENTIAL]], [[RELATIVE], or [[KEYED]] processing, it cannot have a REC= clause, POS= clause or a KEY= clause.		An internal or external file must already be opened and assigned a file number before REREAD can be used. REREAD must follow a successful [[READ]] or REREAD. Although REREAD can be used with [[SEQUENTIAL]], [[RELATIVE]], or [[KEYED]] processing, it cannot have a REC= clause, POS= clause or a KEY= clause.

	In the following example, K$ is a potential key field value entered from the keyboard for a file that allows duplicate keys. These lines of code are one possible way to mix READ and REREAD to be sure that all records are found which exactly match a certain key:		In the following example, K$ is a potential key field value entered from the keyboard for a file that allows duplicate keys. These lines of code are one possible way to mix READ and REREAD to be sure that all records are found which exactly match a certain key:

Laura: /* Technical Considerations */

2013-02-06T02:02:29Z

Technical Considerations

← Older revision		Revision as of 02:02, 6 February 2013
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	<noinclude>		<noinclude>
	[[Category:~~External File Processing Statements]]~~		[[Category:File Processing Statements]]
	~~[[Category:Internal~~ File Processing Statements]]
	[[Category:Statements]]		[[Category:Statements]]
	</noinclude>		</noinclude>

Laura: /* Technical Considerations */

2013-01-31T21:42:30Z

Technical Considerations

← Older revision		Revision as of 21:42, 31 January 2013
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	===Technical Considerations===		===Technical Considerations===
	# Relevant error conditions are: [[CONV]], [[ERROR]], [[EXIT]], [[IOERR]], and [[SOFLOW]].		# Relevant error conditions are: [[CONV]], [[ERROR]], [[EXIT]], [[IOERR]], and [[SOFLOW]].
	# If a string-expr is used with a USING clause, it must begin with "FORM". This technique executes relatively slowly because the string is compiled on each execution of the REREAD statement.		# If a string-expr is used with a USING clause, it must begin with "FORM ". This technique executes relatively slowly because the string is compiled on each execution of the REREAD statement.
	# Omitting the USING clause allows unformatted file processing. See [[File I/O]] for more information.		# Omitting the USING clause allows unformatted file processing. See [[File I/O]] for more information.
	# When [[OPTION INVP]] is in effect, the normal input of commas and periods is interchanged in PIC, N, NZ, G and GZ format specifications to produce European-style numbers. See the [[OPTION]] statement for details.		# When [[OPTION INVP]] is in effect, the normal input of commas and periods is interchanged in PIC, N, NZ, G and GZ format specifications to produce European-style numbers. See the [[OPTION]] statement for details.

Laura: /* Syntax */

2013-01-31T21:35:50Z

Syntax

← Older revision		Revision as of 21:35, 31 January 2013
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	===Syntax===		===Syntax===

	[[Image:Reread.png\|~~800px~~]]		[[Image:Reread.png\|900px]]

	===Defaults===		===Defaults===

Laura: /* Syntax */

2013-01-31T21:34:50Z

Syntax

← Older revision		Revision as of 21:34, 31 January 2013
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	===Syntax===		===Syntax===

	[[Image:Reread.png]]		[[Image:Reread.png\|800px]]

	===Defaults===		===Defaults===

Laura: Created page with "The '''ReRead''' (RER) statement assigns values from the last record read from an internal or external file. ===Comments and Examples=== An internal or external file must..."

2013-01-31T21:21:41Z

Created page with "The '''ReRead''' (RER) statement assigns values from the last record read from an internal or external file. ===Comments and Examples=== An internal or external file must..."

New page

The '''ReRead''' (RER) [[statement]] assigns values from the last record read from an internal or external file.

===Comments and Examples===
An internal or external file must already be opened and assigned a file number before REREAD can be used. REREAD must follow a successful [[READ]] or REREAD. Although REREAD can be used with [[SEQUENTIAL]], [[RELATIVE], or [[KEYED]] processing, it cannot have a REC= clause, POS= clause or a KEY= clause.

In the following example, K$ is a potential key field value entered from the keyboard for a file that allows duplicate keys. These lines of code are one possible way to mix READ and REREAD to be sure that all records are found which exactly match a certain key:

00540 RESTORE #2,KEY=K$: NOKEY 9000
00550 READ #2, USING F2KEYONLY: KY$
00560 IF KY$<>K$ THEN GOTO DONE
00570 REREAD #2, USING F2FULL: MAT A$, MAT AMTS
00580 GOTO 550

Line 550 reads the entire record, but the FORM statement with the label F2KEYONLY only assigns a value to KY$, the key field. If Line 560 finds a match, then the REREAD in line 570 assigns values to all fields in the arrays A$ and AMTS.

===Syntax===

[[Image:Reread.png]]

===Defaults===
# Unformatted.
# Hold all previous locks.
# Interrupt the program if an error occurs and "ON error" is not active.

===Parameters===
"File-num" is an integer or numeric expression which matches this REREAD statement to a file of the same number, already identified in an OPEN statement.

The "USING" keyword is part of a clause which specifies either the "line-ref" of a FORM statement or a "string-expr" containing a FORM statement.

The "RESERVE" and "RELEASE" parameters specify record locking rules for multi-user systems. "RESERVE" instructs the system to hold all previous record locks. "RELEASE" releases all previous record locks.

The "MAT array-name" and "var-name" parameters represent a list of variables to be assigned values. Multiple specifications must be separated by commas.

REREAD allows error processing with the optional "error-cond line-ref" parameter. See [[Error Conditions]] for more information.

===Technical Considerations===
# Relevant error conditions are: [[CONV]], [[ERROR]], [[EXIT]], [[IOERR]], and [[SOFLOW]].
# If a string-expr is used with a USING clause, it must begin with "FORM". This technique executes relatively slowly because the string is compiled on each execution of the REREAD statement.
# Omitting the USING clause allows unformatted file processing. See [[File I/O]] for more information.
# When [[OPTION INVP]] is in effect, the normal input of commas and periods is interchanged in PIC, N, NZ, G and GZ format specifications to produce European-style numbers. See the [[OPTION]] statement for details.

<noinclude>
[[Category:External File Processing Statements]]
[[Category:Internal File Processing Statements]]
[[Category:Statements]]
</noinclude>