UniBasic Commands Reference - Rocket Software
UniBasic Commands Reference - Rocket Software UniBasic Commands Reference - Rocket Software
READXFWD Syntax READXFWD dyn.array.var [FROM file.var] [ON ERROR statements] {THEN statements [END] | ELSE statements [END]} Description The UniBasic READXFWD command reads the next value in an alternate key index in much the same manner as the READFWD command, but does not read the associated record. READXFWD enables a program to read alternate keys without incurring the overhead of retrieving a record every time. Parameters The following table describes each parameter of the syntax. Parameter Description 1-658 UniBasic Commands Reference dyn.array.var Specifies a dynamic array to which to assign the values read. FROM file.var Specifies the file from which to read the record. If you do not specify a file.var, UniData reads from the default file. If no default file is open, a fatal error occurs. The default file is one for which no file variable is assigned in the OPEN statement. READXFWD Parameters
Parameter Description ON ERROR statements Specifies statements to execute if the READXFWD statement fails with a fatal error because the file is not open, an I/O error occurs, or UniData cannot find the file. If you do not specify the ON ERROR clause and a fatal error occurs, the program terminates. THEN statements END THEN executes if the read is successful. END is required to terminate multiline THEN statements. ELSE statements END ELSE executes if the read is not successful or the record does not exist. END is required to terminate multiline ELSE statements. Related Commands UniBasic READBCK, READBCKL, READBCKU, READFWD, READFWDL, READFWDU, READXBCK, SELECTINDEX, SETINDEX UniData READXFWD Parameters (continued) BUILD.INDEX, CREATE.INDEX – For information, see the UniData Commands Reference. READXFWD 1-659
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- Page 652 and 653: READFWD Syntax READFWD dyn.array.va
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- Page 670 and 671: READNEXT Syntax READNEXT id.var [,
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- Page 674 and 675: READNEXTTUPLE Syntax READNEXTTUPLE
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- Page 678 and 679: READSEQ Syntax READSEQ var FROM seq
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- Page 682 and 683: READT Syntax READT [UNIT (mu.expr)]
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- Page 688 and 689: Related Commands UniBasic CLOSE, DE
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- Page 692 and 693: READVL Syntax READVL var FROM [file
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- Page 698 and 699: READXBCK Syntax READXBCK dyn.array.
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- Page 704 and 705: RECORDLOCKED Syntax RECORDLOCKED (f
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- Page 714 and 715: ReleaseXML Syntax ReleaseXML(XMLhan
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- Page 722 and 723: REMOVE Syntax REMOVE(dyn.array.var,
- Page 724 and 725: REPLACE Syntax REPLACE(dyn.array.ex
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- Page 730 and 731: RETURN Syntax RETURN [TO label[:]]
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READXFWD<br />
Syntax<br />
READXFWD dyn.array.var [FROM file.var] [ON ERROR statements]<br />
{THEN statements [END] | ELSE statements [END]}<br />
Description<br />
The <strong>UniBasic</strong> READXFWD command reads the next value in an alternate key index<br />
in much the same manner as the READFWD command, but does not read the<br />
associated record. READXFWD enables a program to read alternate keys without<br />
incurring the overhead of retrieving a record every time.<br />
Parameters<br />
The following table describes each parameter of the syntax.<br />
Parameter Description<br />
1-658 <strong>UniBasic</strong> <strong>Commands</strong> <strong>Reference</strong><br />
dyn.array.var Specifies a dynamic array to which to assign the values read.<br />
FROM file.var Specifies the file from which to read the record.<br />
If you do not specify a file.var, UniData reads from the default<br />
file. If no default file is open, a fatal error occurs.<br />
The default file is one for which no file variable is assigned in<br />
the OPEN statement.<br />
READXFWD Parameters
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