LOCATE

LOCATE

Search sequentially for a record matching a condition

Syntax

      LOCATE [<scope>] FOR <lCondition>
             [WHILE <lCondition>]

Arguments

<scope> is the portion of the current database file in which to perform the LOCATE. The default scope is ALL records.

FOR <lCondition> specifies the next record to LOCATE within the given scope.

WHILE <lCondition> specifies the set of records meeting the condition from the current record until the condition fails.

Description

LOCATE is a database command that searches for the first record in the current work area that matches the specified conditions and scope. When you first execute a LOCATE, it searches from the beginning record of the scope for the first matching record in the current work area. It terminates when a match is found or the end of the LOCATE scope is reached. If it is successful, the matching record becomes the current record and FOUND() returns true (.T.). If it is unsuccessful, FOUND() returns false (.F.) and the positioning of the record pointer depends on the controlling scope of the LOCATE.

Each work area can have its own LOCATE condition. The condition remains active until you execute another LOCATE command in that work area or the application terminates.

LOCATE works with CONTINUE. Once a LOCATE has been issued, you can resume the search from the current record pointer position with CONTINUE. There are, however, some exceptions. See note below.

Notes

. CONTINUE: Both the <scope> and the WHILE condition apply only to the initial LOCATE and are not operational for any subsequent CONTINUE commands. To continue a pending LOCATE with a scope or WHILE condition, use SKIP then LOCATE REST WHILE <lCondition> instead of CONTINUE.

Examples

      .  These examples show typical LOCATEs:
      USE Sales INDEX Salesman
      LOCATE FOR Branch = "200"
      ? FOUND(), EOF(), RECNO()         // Result: .T. .F. 5
      LOCATE FOR Branch = "5000"
      ? FOUND(), EOF(), RECNO()         // Result: .F. .T. 85
      .  This example shows a LOCATE with a WHILE condition that is
         continued by using LOCATE REST:
      SEEK "Bill"
      LOCATE FOR Branch = "200" WHILE Salesman = "Bill"
      DO WHILE FOUND()
         ? Branch, Salesman
         SKIP
         LOCATE REST FOR Branch = "200" WHILE ;
                  Salesman = "Bill"
      ENDDO

Seealso

CONTINUE, EOF(), FOUND(), SEEK, SET FILTER

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Found()

FOUND()

Determine the success of a previous search operation.

Syntax

      FOUND() --> lSuccess

Arguments

(This function has no arguments)

Returns

<lSuccess> A logical true (.T.) is successful; otherwise, false (.F.)

Description

This function is used to test if the previous SEEK, LOCATE, CONTINUE, or FIND operation was successful. Each wrk area has its own FOUND() flag, so that a FOUND() condition may be tested in unselected work areas by using an alias.

Examples

      nId := 100
      USE tests NEW INDEX tests
      SEEK nId
      IF FOUND()
         ? tests->Name
      ENDIF
      USE

Compliance

Clipper

Files

Library is rdd

Seealso

EOF()

SP_SEARCHMRS

SEARCHMRS()

  Short:
  ------
  SEARCHMRS() Resets all SEARCHME() settings

  Returns:
  --------
  NIL

  Syntax:
  -------
  SEARCHMRS([)

  Description:
  ------------
  Resets all SEARCHME() static variables
    - sets found() flag to FALSE
    - sets locate block to nil
    - sets continue flag to .f.
    - sets ALIAS to nil

  For instance, if you change datafiles - you need to reset
  SEARCHME() with SEARMRS()

  Examples:
  ---------
  SEARCHMRS()

  Source:
  -------
  S_SEARCH.PRG

 

SP_SEARCHMFND

SEARCHMFND()

  Short:
  ------
  SEARCHMFND() Set/return last found() status from SEARCHME()

  Returns:
  --------
  <lFound> -> Last searchme found() status

  Syntax:
  -------
  SEARCHMFND([lSet])

  Description:
  ------------
  Sets/retrieves the last found() setting for SEARCHME()
  [lSet] optionally sets the found() flag.

  For instance, to find out what the last result of SEARCHME() was
  so you can take an action or not based on something being found,
  use SEARCHMFND() to retrieve the last result.

  Examples:
  ---------
  SEARCHMFND(.f.)

  Source:
  -------
  S_SEARCH.PRG

 

SP_SEARCHME

SEARCHME()

  Short:
  ------
  SEARCHME() Search a DBF with user-specified criteria

  Returns:
  --------
  <bSearch> -> The code block used to do the search

  Syntax:
  -------
  SEARCHME([aField,aFieldTypes,aFieldLengths],[aFieldDesc])

  Description:
  ------------
  Searches the current dbf with criteria given

  by the user.

       for :    Field Contents Match
                Query match  --->> calls QUERY()
                End of file
                Beginning of File
                Deleted Records
                Memo contents

  On subsequent calls, if the previous search resulted
  in a FOUND(), a box asking "Continue..", "New Search" will pop up.
  If CONTINUE is selected, a continuation of the last search is
  done.

  Three arrays may be passed for FIELDS [aFields],
  FIELD TYPES [aFieldTypes], and FIELD LENGTHS [aFieldLengths].

  An additional (optional) array of field descriptions may be passed

  Default is all fields, field names as descriptions.

  Searchme() actually returns the code block used to do the
  search. Normally you would want to ignore this. I use it in
  TAGIT() - if the code block is not NIL, then I can 'tag all
  matching' with it.

  Examples:
  ---------
  SEARCHME()

  Source:
  -------
  S_SEARCH.PRG

 

C5_CONTINUE

 CONTINUE
 Resume a pending LOCATE
------------------------------------------------------------------------------
 Syntax

     CONTINUE

 Description

     CONTINUE is a database command that searches from the current record
     position for the next record meeting the most recent LOCATE condition
     executed in the current work area.  It terminates when a match is found
     or end of file is encountered.  If CONTINUE is successful, the matching
     record becomes the current record and FOUND() returns true (.T.); if
     unsuccessful, FOUND() returns
     false (.F.).

     Each work area may have an active LOCATE condition.  In Clipper, a
     LOCATE condition remains pending until a new LOCATE condition is
     specified.  No other commands release the condition.

 Notes

     .  Scope and WHILE condition: Note that the scope and WHILE
        condition of the initial LOCATE are ignored; only the FOR condition
        is used with CONTINUE.  If you are using a LOCATE with a WHILE
        condition and want to continue the search for a matching record, use
        SKIP and then repeat the original LOCATE statement adding REST as the
        scope.

 Examples

     .  This example scans records in Sales.dbf for a particular
        salesman and displays a running total sales amounts:

        LOCAL nRunTotal := 0
        USE Sales NEW
        LOCATE FOR Sales->Salesman = "1002"
        DO WHILE FOUND()
           ? Sales->Salesname, nRunTotal += Sales->Amount
           CONTINUE
        ENDDO

     .  This example demonstrates how to continue if the pending
        LOCATE scope contains a WHILE condition:

        LOCAL nRunTotal := 0
        USE Sales INDEX Salesman NEW
        SEEK "1002"
        LOCATE REST WHILE Sales->Salesman = "1002";
              FOR Sales->Amount > 5000
        DO WHILE FOUND()
           ? Sales->Salesname, nRunTotal += Sales->Amount
           SKIP
           LOCATE REST WHILE Sales->Salesman = "1002";
              FOR Sales->Amount > 5000
        ENDDO

 Files   Library is CLIPPER.LIB.

See Also: EOF() FOUND() LOCATE SEEK

 

C5 Commands

 ?|??            Display one or more values to the console
 @...BOX         Draw a box on the screen
 @...CLEAR       Clear a rectangular region of the screen
 @...GET         Create a new Get object and display it
 @...PROMPT      Paint a menu item and define a message
 @...SAY         Display data at a specified screen or printer row and column
 @...TO          Draw a single- or double-line box
 ACCEPT*         Place keyboard input into a memory variable
 APPEND BLANK    Add a new record to the current database file
 APPEND FROM     Import records from a database (.dbf) file or ASCII text file
 AVERAGE         Average numeric expressions in the current work area
 CALL*           Execute a C or Assembler procedure
 CANCEL*         Terminate program processing
 CLEAR ALL*      Close files and release public and private variables
 CLEAR GETS      Release Get objects from the current GetList array
 CLEAR MEMORY    Release all public and private variables
 CLEAR SCREEN    Clear the screen and return the cursor home
 CLEAR TYPEAHEAD Empty the keyboard buffer
 CLOSE           Close a specific set of files
 COMMIT          Perform a solid-disk write for all active work areas
 CONTINUE        Resume a pending LOCATE
 COPY FILE       Copy a file to a new file or to a device
 COPY STRUCTURE  Copy the current .dbf structure to a new database (.dbf) file
 COPY STRU EXTE  Copy field definitions to a .dbf file
 COPY TO         Export records to a database (.dbf) file or ASCII text file
 COUNT           Tally records to a variable
 CREATE          Create an empty structure extended (.dbf) file
 CREATE FROM     Create a new .dbf file from a structure extended file
 DELETE          Mark records for deletion
 DELETE FILE     Remove a file from disk
 DELETE TAG      Delete a tag
 DIR*            Display a listing of files from a specified path
 DISPLAY         Display records to the console
 EJECT           Advance the printhead to top of form
 ERASE           Remove a file from disk
 FIND*           Search an index for a specified key value
 GO              Move the pointer to the specified identity
 INDEX           Create an index file
 INPUT*          Enter the result of an expression into a variable
 JOIN            Create a new database file by merging from two work areas
 KEYBOARD        Stuff a string into the keyboard buffer
 LABEL FORM      Display labels to the console
 LIST            List records to the console
 LOCATE          Search sequentially for a record matching a condition
 MENU TO         Execute a lightbar menu for defined PROMPTs
 NOTE*           Place a single-line comment in a program file
 PACK            Remove deleted records from a database file
 QUIT            Terminate program processing
 READ            Activate full-screen editing mode using Get objects
 RECALL          Restore records marked for deletion
 REINDEX         Rebuild open indexes in the current work area
 RELEASE         Delete public and private memory variables
 RENAME          Change the name of a file
 REPLACE         Assign new values to field variables
 REPORT FORM     Display a report to the console
 RESTORE         Retrieve memory variables from a memory (.mem) file
 RESTORE SCREEN* Display a saved screen
 RUN             Execute a DOS command or program
 SAVE            Save variables to a memory (.mem) file
 SAVE SCREEN*    Save the current screen to a buffer or variable
 SEEK            Search an order for a specified key value
 SELECT          Change the current work area
 SET ALTERNATE   Echo console output to a text file
 SET BELL        Toggle sounding of the bell during full-screen operations
 SET CENTURY     Modify the date format to include or omit century digits
 SET COLOR*      Define screen colors
 SET CONFIRM     Toggle required exit key to terminate GETs
 SET CONSOLE     Toggle console display to the screen
 SET CURSOR      Toggle the screen cursor on or off
 SET DATE        Set the date format for input and display
 SET DECIMALS    Set the number of decimal places to be displayed
 SET DEFAULT     Set the CA-Clipper default drive and directory
 SET DELETED     Toggle filtering of deleted records
 SET DELIMITERS  Toggle or define GET delimiters
 SET DESCENDING  Change the descending flag of the controlling order
 SET DEVICE      Direct @...SAYs to the screen or printer
 SET EPOCH       Control the interpretation of dates with no century digits
 SET ESCAPE      Toggle Esc as a READ exit key
 SET EXACT*      Toggle exact matches for character strings
 SET EXCLUSIVE*  Establish shared or exclusive USE of database files
 SET FILTER      Hide records not meeting a condition
 SET FIXED       Toggle fixing of the number of decimal digits displayed
 SET FORMAT*     Activate a format when READ is executed
 SET FUNCTION    Assign a character string to a function key
 SET INDEX       Open one or more order bags in the current work area
 SET INTENSITY   Toggle enhanced display of GETs and PROMPTs
 SET KEY         Assign a procedure invocation to a key
 SET MARGIN      Set the page offset for all printed output
 SET MEMOBLOCK   Change the block size for memo files
 SET MESSAGE     Set the @...PROMPT message line row
 SET OPTIMIZE    Change the setting that optimizes using open orders
 SET ORDER       Select the controlling order
 SET PATH        Specify the CA-Clipper search path for opening files
 SET PRINTER     Toggle echo of output to printer or set the print destination
 SET PROCEDURE*  Compile procedures and functions into the current object file
 SET RELATION    Relate two work areas by a key value or record number
 SET SCOPE       Change the boundaries for scoping keys in controlling order
 SET SCOPEBOTTOM Change bottom boundary for scoping keys in controlling order
 SET SCOPETOP    Change top boundary for scoping keys in controlling order
 SET SCOREBOARD  Toggle the message display from READ or MEMOEDIT()
 SET SOFTSEEK    Toggle relative seeking
 SET TYPEAHEAD   Set the size of the keyboard buffer
 SET UNIQUE*     Toggle inclusion of non-unique keys into an index
 SET WRAP*       Toggle wrapping of the highlight in menus
 SKIP            Move the record pointer to a new position
 SORT            Copy to a database (.dbf) file in sorted order
 STORE*          Assign a value to one or more variables
 SUM             Sum numeric expressions and assign results to variables
 TEXT*           Display a literal block of text
 TOTAL           Summarize records by key value to a database (.dbf) file
 TYPE            Display the contents of a text file
 UNLOCK          Release file/record locks set by the current user
 UPDATE          Update current database file from another database file
 USE             Open an existing database (.dbf) and its associated files
 WAIT*           Suspend program processing until a key is pressed
 ZAP             Remove all records from the current database file