Keyed access procedures are legal only on files opened for keyed access.
1 – FINDK
The FINDK procedure searches the index of an indexed file opened for keyed access and locates a specific component. Syntax: FINDK( file_variable, key-number, key-value[[, match-type]] [[, ERROR := error-recovery]] ); The 'file_variable' is the name of the file variable associated with the file to be searched. The 'key-number' is a positive integer expression that indicates the key position. The 'key-value' is an expression that indicates the key to be found. It must be assignment compatible with the key field in the specified key position. The 'match-type' is an identifier that indicates the relationship between the key value in the FINDK procedure call and key value of a component. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. When you establish key fields with the KEY attribute, you assign each one a key number from 0 to 254. Key number 0 represents the mandatory primary key of the file. Separate indexes are built for each key number in the file. The key value and the match type provide information about the key to be found. The key value must be assignment compatible with the key fields of the key number being searched. The match type must be EQL (equal to the key value), NXT (the next key in the collating sequence after the key value), or NXTEQL (the next or equal key in the collating sequence after the key value). If the FINDK procedure was used on an ascending collating sequence, NXT and NXTEQL would be equivalent to GTR and GEQ. If a descending collating sequence was used, it would be the same as LSS and LEQ. The match type is optional; if omitted, it defaults to EQL. The FINDK procedure can be called for any indexed file opened for keyed access, regardless of the file's mode. If the component described exists, the file buffer is filled with that component; UFB and EOF both become FALSE. The mode is set to inspection and the component is automatically locked. If no component is found to match the description, UFB becomes TRUE and EOF is undefined. The mode is set to undefined. See the "HP Pascal Language Reference Manual" for complete information on the FINDK procedure.
2 – RESETK
The RESETK procedure, like the RESET procedure, readies a file for reading. Syntax: RESETK( file_variable, key-number[[, ERROR := error-recovery]] ); The 'file_variable' is the name of the file variable associated with the input file. The 'key-number' is a positive integer expression that indicates the key position. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. The file can be in any mode before RESETK is called to set the mode to inspection. RESETK can be applied only to indexed files opened for random access by key. You assign a key number from 0 to 254 to each key field of a file component with the KEY attribute. The file is searched for the component with the lowest value in the specified key number. This component becomes the current component in the file and is locked. The value of the current component is copied into the file buffer; EOF and UFB are set to FALSE. If the component does not exist, EOF and UFB become TRUE. Note that a RESETK procedure on key number 0 is equivalent to a RESET procedure. See the "HP Pascal Language Reference Manual" for complete information on the RESETK procedure.