Discussion:
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The DELETE statement deletes an existing record from a
keyed file.
The parameter defines which file the record being deleted
from (i.e., the file opened under that lun in a previous
OPEN statement).
The index parameter defines the index and associated record being
deleted. The index may be a string constant, a single-element
string variable, a string array element, a string expression, or
a string function.
When the DELETE statement is executed, it automatically advances
the file pointer to the next available record in sequential (key)
order, marks the record for deletion, and removes the specified
key from the key list.
Example 1:
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DELETE (3) KEY="ABC-123",EXCP=5000
In this example, a record is deleted from the file opened on
logical unit number 3. The key containing "ABC-123" specifies the
record to be deleted from the file. If an exception occurs when
this statement is executed (e.g., if the key doesn't exist in the
file), the program will branch to statement-label 5000.
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Example 2:
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OPEN (1) "DATAFILE"
.
.
.
PRINT (0) "ENTER KEY TO DELETE:"
INPUT (0) KEYVALUE$
DELETE (1) KEY=KEYVALUE$,EXCP=9999
In this example, the user is prompted for a specific key value.
The response is then used to determine which key and record will
be deleted from the file opened on logical unit number 1.
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