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Returns a specific line from a Memo field as a character string.
 Note: |
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| MLINE(В ) is primarily a text processing function; therefore, the results from processing binary values might not be as expected. For example, MLINE(В ) might return different results depending on the SET MEMOWIDTH setting. MLINE(В ) might interpret binary values as line breaks or truncate binary values unexpectedly. It is recommended that you use the ALINES(В ) function instead to manipulate binary values. |
MLINE(MemoFieldName, nLineNumber [, nNumberOfCharacters]) |
Parameters
- MemoFieldName
- Specifies the name of the memo field from which MLINE(В ) returns a line. If the memo field is in a table open in a non-current work area, preface the memo field name with a period and the table alias.
- nLineNumber
- Specifies the number of the line to return from the memo field. If nLineNumber is negative, 0, or greater than the number of lines in the memo field, MLINE(В ) returns an empty string. MLINE(В ) trims any trailing spaces from the line specified with nLineNumber.
- nNumberOfCharacters
- Specifies the number of characters from the beginning of the memo field after which MLINE(В ) returns the specified line. The _MLINE system variable is typically used for nNumberOfCharacters. _MLINE is automatically adjusted each time MLINE(В ) is called. In recursive procedures that return lines from large memo fields, you can obtain the best performance by including _MLINE as nNumberOfCharacters. For more information, see _MLINE System Variable.
Return Value
Character or Varbinary. MLINE( ) returns a character string from a specific line in a Memo field. When using MLINE(В ) with binary values, such as Varbinary and Blob, the return value has type Varbinary.
Remarks
The length and number of the lines in a memo field are determined by the current value of SET MEMOWIDTH (the default line length is 50 characters). If a carriage return is encountered, no additional characters are returned. The current _WRAP setting determines how the memo field line is displayed.
When searching a memo field for a character string, you can use ATLINE(В ) or ATCLINE(В ) to return the line number of the line in which the character string is found. Use this line number in MLINE(В ) to return the contents of the line from the memo field.
Example
In the following example, two methods are used to return lines from a memo field. Two loops use MLINE(В ) to return lines from the memo field. Note the improvement in performance in the second loop when the system variable _MLINE is used in MLINE(В ).
| В |  Copy Code |
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CLEAR
SET TALK OFF
SET MEMOWIDTH TO 50
CLOSE DATABASES
CREATE TABLE tmemo (name c(10), notes m)
APPEND BLANK && Add a record
WAIT WINDOW 'Filling memo field - takes several seconds' NOWAIT
*** Fill the memo field ***
FOR gnOuterLoop = 1 TO 5 && loop 5 times
FOR gnAlphabet = 65 TO 75 && letters A to H
REPLACE notes WITH REPLICATE(CHR(gnAlphabet), 10) ;
+ CHR(13) ADDITIVE
NEXT
NEXT
*** Display all lines from the memo field ***
STORE MEMLINES(notes) TO gnNumLines && Number of lines in memo field
STORE SECONDS( ) TO gnBegin && Beginning time
FOR gnCount = 1 TO gnNumLines && Loop for # of lines in memo field
? MLINE(notes, gnCount) && Display each line
NEXT
? STR(SECONDS( ) - gnBegin, 4, 2) + ' seconds' && Total time
*** Preferable method using _MLINE in MLINE( ) ***
*** Display all lines from the memo field ***
WAIT 'Press a key to see the preferred method' WINDOW
CLEAR
STORE 0 TO _MLINE && Reset _MLINE to zero
STORE SECONDS( ) TO gnBegin && Beginning time
FOR count = 1 TO gnNumLines && Loop for # of lines in memo field
? MLINE(notes, 1, _MLINE) && Display each line
NEXT
? STR(SECONDS( ) - gnBegin, 4, 2) + ' seconds' && Total time
SET TALK ON
CLOSE DATABASES
ERASE tmemo.dbf
ERASE tmemo.fpt | |