Transcript Some of Visual Foxpro`s Commands

SET DEFAULT Command
•Function: Specifies the default drive and
directory.
•Syntax:
SET DEFAULT TO [cPath]
Parameters
cPath. Specifies one of the following:
•A drive designator
•A drive designator with a directory name
•A child directory name
•Any of the above using Microsoft MS-DOS
shorthand notation ( \ or ..)
Remarks
•SET DEFAULT changes the default directory to
the directory you specify.
•Microsoft® Visual FoxPro® searches for a file in
the default Visual FoxPro directory. The default
directory is the one from which you start Visual
FoxPro. However, you can specify a different
default directory in your Visual FoxPro
configuration file or in a startup program.
Remarks…
•If Visual FoxPro cannot find a file in the default
directory, it then searches the Visual FoxPro
path if one has been specified. Use SET PATH to
specify the Visual FoxPro path.
•If you create a file and do not specify where to
place it, the file is placed in the default Visual
FoxPro directory.
Remarks…
•The SET DEFAULT command is not supported in
either single or multithreaded DLL servers. This
command changes the default directory of the
entire process, so all threads which are part of
the process are affected. Use the SET PATH
command in DLL servers, in place of CD and
CHDIR.
 Tips
•SYS(5) returns the default drive.
•SYS(2003) returns the default directory with no
drive designator.
•SYS(5) + SYS(2003) returns the default drive and
the directory.
Examples
Set Default to D
&& Changes default drive to D
Set Default to D:
&& Changes default drive to D
Set Default to D:\Bruno\Exercises
Set Default to D:\Bruno && Specifies a specific directory
Set Default to Exercises && Changes the default
directory to D:\Exercises if the root directory on drive D is the
default directory of Visual Foxpro.
Note: && indicates the start of an inline comment.
Examples…
Set Default to \
&& Makes the root directory the
default directory – that is, if the current directory is other
than the root directory (e.g., D:\Bruno\Exercises)
Set Default to ..
&& Moves the default directory one
level (up) towards the root directory.
CREATE Command
•Function: Opens the Table Designer so you can
create a Visual FoxPro table.
•Syntax:
Create [filename│?]
Parameters
[ FileName| ?] Specifies the name of the table to
create or opens the Create dialog box so you can
browse for a location to save the table and
specify the name of the table to create.
• If FileName is specified, it opens the Table Designer so you
could define the fields and their attributes in the table.
• If ? is used, it opens the Create dialog box so you can
browse for a location to save the table and specify the
name of the table to create.
Remarks
•If a database is open when you create a table, the
table is added automatically to the database.
•When running on the Windows operating system,
you cannot create a table with the name of an MSDOS device, such as CON, NUL, PRN, and COM1.
Avoid using hyphens in a table name because
hyphenated table names do not appear in the Data
Session window and can cause confusion with the
alias pointer (->).
Remarks…
•After opening the Table Designer, you need to
define attributes for the fields in the table. After
you create the table structure, you can add records
to the table. For more information, see Creating
Tables.
•The SQL CREATETABLE command makes it possible
to specify fields and their attributes
programmatically. For more information, see
CREATE TABLE - SQL Command.
Examples
Set Default to F:\Bruno
Create Students
Set Default to D:\Bruno
Create ?
APPEND Command
•Function: Adds one or more new records to the
end of a table.
•Syntax:
APPEND [BLANK] [IN nWorkArea | cTableAlias]
[NOMENU]
Parameters
BLANK adds one blank record to the end of the
current table. Visual FoxPro does not open an
editing window when you issue APPEND BLANK.
You can edit the new record with BROWSE,
CHANGE, or EDIT.
IN nWorkArea specifies the work area of the
table to which a new record is appended.
Parameters…
IN cTableAlias specifies the alias of the table to which
a new record is appended. If you omit nWorkArea and
cTableAlias, a new record is appended to the table in
the currently selected work area. If you issue APPEND,
a blank record is added to the table you specify with
nWorkArea or cTableAlias and the table is
automatically selected. If you issue APPEND BLANK, a
blank record is added to the table you specify with
nWorkArea or cTableAlias and the table is not selected.
Parameters…
NOMENU specifies that the Table menu title is
removed from the system menu bar, preventing
changes to the format of the editing window.
DELETE Command
•Function: Marks records for deletion.
•Syntax:
DELETE [Scope] [FOR lExpression1] [WHILE
lExpression2] [IN nWorkArea | cTableAlias]
[NOOPTIMIZE]
Parameters
Scope. Specifies a range of records to mark for
deletion. The default scope for DELETE is the
current record (NEXT 1). The scope clauses are:
ALL, NEXT nRecords, RECORD nRecordNumber,
and REST. For more information on scope
clauses, see Scope Clauses.
Parameters…
FOR lExpression1. Specifies a condition whereby only
the records that satisfy the logical condition lExpression1
are marked for deletion. Rushmore Query Optimization
optimizes a query created with DELETE ... FOR if
lExpression1 is an optimizable expression and the table is
indexed on DELETED( ). For best performance, use an
optimizable expression in the FOR clause. For information
on Rushmore optimizable expressions, see SET OPTIMIZE,
and Using Rushmore Query Optimization to Speed Data
Access in Optimizing Applications.
Parameters…
WHILE lExpression2. Specifies a condition
whereby records are marked for deletion for as
long as lExpression2 evaluates to true (.T.).
IN nWorkArea. Specifies the work area of the
table in which records are marked for deletion.
Parameters…
IN cTableAlias. Specifies the alias of the table in
which records are marked for deletion. If you
omit nWorkArea and cTableAlias, records are
marked for deletion in the table in the currently
selected work area.
NOOPTIMIZE. Disables Rushmore optimization of
DELETE.
Remarks
•Records marked for deletion aren't physically
removed from the table until PACK is issued.
Records marked for deletion can be recalled
(unmarked) with RECALL.
Example
The following example opens the Customer table
in the TestData database. DELETE is used to mark
all records for deletion where the Country field
contains USA. All the records marked for deletion
are displayed. RECALL ALL is used to unmark all
records marked for deletion.
Example…
CLOSE DATABASES
OPEN DATABASE (HOME(2) + 'Data\testdata')
USE customer && Opens Customer table
DELETE FOR country = 'USA' && Marks for deletion
CLEAR
LIST FIELDS company, country FOR DELETED( ) && Lists
marked records
RECALL ALL && Unmark all records marked for
deletion.
SET PATH Command
•Function: Specifies a path for file searches.
•Syntax:
SET PATH TO [Path] [ADDITIVE]
Parameters
TO [Path] specifies the directories you want
Visual FoxPro to search. Use commas or
semicolons to separate the directories.
[ADDITIVE] appends additional paths to the end
of the current path.
 Note
•Visual FoxPro will not recognize a path name
properly if a disk or directory name contains an
exclamation point (!)
•On all FoxPro platforms, functions that return
path information, such as CURDIR( ), DBF( ), and
SYS(2003), use Microsoft MS-DOS path-naming
conventions in their return values.
Remarks
• Issue SET PATH TO without Path to restore the path to
the default directory. Use SET DEFAULT to specify the
default directory and CURDIR( ) to return the current
default directory.
• SET PATH is not scoped to the current data session;
changes you make to the default path using the SET PATH
command affect all data sessions.
• SET PATH is limited to a maximum of 4095 characters.
• When using the ADDITIVE parameter, paths must be
included either as a quoted string or valid expression.
Examples
ff = [“Bruno3"]
SET PATH TO &ff ADDITIVE
** or **
ff = “Bruno3“
SET PATH TO '&ff' ADDITIVE
Note: * indicates the start of a line comment.
Go │ Goto Command
• Function: Moves the record pointer to the specified record
number.
• Syntaxes:
• GO [RECORD] nRecordNumber [IN nWorkArea | IN
cTableAlias]
• GO TOP | BOTTOM [IN nWorkArea | IN cTableAlias]
• GOTO [RECORD] nRecordNumber [IN nWorkArea | IN
cTableAlias]
• GOTO TOP | BOTTOM [IN nWorkArea | IN cTableAlias]
Parameters
•RECORD nRecordNumber. Specifies the physical
record number to move the record pointer to.
You can omit GO or GOTO entirely and specify
just the record number. If you specify just the
record number, you can move the record
pointer only within the current work area.
•IN nWorkArea. Specifies the work area of the
table in which the record pointer is moved.
Parameters …
•IN cTableAlias. Specifies the alias of the table in
which the record pointer is moved.
•TOP. Positions the record pointer on the first
record in the table. If the table has an ascending
index in use, the first record is the record with the
lowest key value. If the index is in descending
order, the first record is the record with the
highest key value.
Parameters …
•BOTTOM. Positions the record pointer on the
last record in the table. If the table has an
ascending index in use, the last record is the
record with the highest key value. If the index is
in descending order, the last record is the
record with the lowest key value.
Remarks
•GO and GOTO can be used interchangeably.
These commands operate on the table in the
current work area unless you specify another
work area with the IN clause.
Example
CLOSE DATABASES
OPEN DATABASE (HOME(2) + 'data\testdata')
USE products && Opens Products table
USE customer IN 0 && Opens Customer table
GO BOTTOM IN products
CLEAR
? RECNO('products')
GO TOP
? RECNO( ) && Displays 1
GO 5
? RECNO( ) && Displays 5
? │ ?? Command
• Function: Evaluates expressions and sends the
results to the main Visual FoxPro window, an
active user-defined window, or the printer.
• Syntax:
•? | ?? Expression1 [PICTURE cFormatCodes] |
[FUNCTION cFormatCodes] | [VnWidth] [AT
nColumn] [FONT cFontName [, nFontSize [,
nFontCharSet]] [STYLE cFontStyle |
Expression2]] [, Expression3] …
Parameters
•? Expression1. Evaluates the expression
specified by Expression1 and sends a carriage
return and line feed preceding the expression
results. The results display on the next line of
the main Visual FoxPro window or the active
user-defined window and are printed at the left
margin of a page unless a function code
specified by cFormatCodes or the _ALIGNMENT
system variable specifies otherwise.
Parameters…
If you omit the expressions, a blank line is
displayed or printed. A space is placed between
expression results when multiple expressions are
included. If Expression1 is an object, the ?
command returns the character string,
"(Object)".
Parameters…
•?? Expression1. Evaluates the expression
specified by Expression1 and displays the
expression results on the current line at the
current position of the main Visual FoxPro
window, an active user-defined window, or the
printer. A carriage return and line feed are not
sent before the results.
Parameters…
•PICTURE cFormatCodes. Specifies a picture
format in which the result of Expression1 is
displayed. cFormatCodes can consist of function
codes, picture codes, or a combination of both.
You can use the same codes available in the
Format Property and InputMask Property.
Function codes affect the overall format of the
result; picture codes act on individual
characters in the result.
Parameters…
If function codes are used in cFormatCodes, they
must appear before the picture codes and they
must be preceded by an at (@) sign. Multiple
function codes with no embedded spaces can
immediately follow the @ sign. The last function
code must be followed by one or more spaces.
The space or spaces signal the end of the
function codes and the start of the picture
codes.
Parameters…
•FUNCTION cFormatCodes. Specifies a function
code to include in the output from the ? and ??
commands. If the function clause is included,
do not precede the function codes with an @
sign. Function codes must be preceded by a @
sign when included in PICTURE.
Parameters…
•V nWidth. Specifies a special function code that
enables the results of a character expression to
stretch vertically within a limited number of
columns. nWidth specifies the number of
columns in the output.
? 'This is an example of how the V function code
works.' ;
FUNCTION 'V10'
Parameters…
•AT nColumn. Specifies the column number
where the output is displayed. This option
makes it possible for you to align output in
columns to create a table. The numeric
expression nColumn can be a user-defined
function that returns a numeric value.
Parameters…
•FONT cFontName[, nFontSize [, nFontCharSet]].
Specifies a font for output by the ? or ??
command. cFontName specifies the name of
the font, and nFontSize specifies the point size.
You can specify a language script with
nFontCharSet. See the GETFONT( ) Function for
a list of available language script values. For
example, the following command displays the
system date in 16-point Courier font:
Parameters…
•FONT cFontName[, nFontSize [, nFontCharSet]].
Specifies a font for output by the ? or ?? command.
cFontName specifies the name of the font, and
nFontSize specifies the point size. You can specify a
language script with nFontCharSet. See the GETFONT(
) Function for a list of available language script values.
For example, the following command displays the
system date in 16-point Courier font:
• ? DATE( ) FONT 'Courier',16
Parameters…
If you include the FONT clause but omit the point size
nFontSize, a 10-point font is used. If you omit the FONT
clause, and output for the ? or ?? command is placed in
the main Visual FoxPro window, the main Visual FoxPro
window font is used for the output. If you omit the
FONT clause, and output for the ? or ?? command is
placed in a user-defined window, the user-defined
window font is used for the output.
 Note: If the font you specify is not available, a font with similar
font characteristics is substituted.
??? Command
•Function: Sends output directly to the printer.
•Syntax:
•??? cExpression
Parameters
•cExpression. Specifies the characters that are
sent to the printer.
Remarks
• A group of three question marks bypasses the printer driver and
sends the contents of cExpression directly to the printer.
cExpression must contain valid printer codes.
• Printer control codes make it possible for you to reset the printer,
change type styles and sizes, and enable or disable boldface
printing. These codes can consist of any combination of printable
or nonprintable characters that are specific to the printer you are
using. You can direct control codes to the printer in several
different ways:
• Use combinations of CHR( ) and quoted strings concatenated
with + to send ASCII characters directly to the printer.
Remarks…
• Tables store data in a row and column format, similar to a
spreadsheet. Each row represents a record, and each column
represents the fields in each record. Tables in Visual FoxPro
can exist as a free table or as a database table.
• A free table is a table (.dbf) file that is not associated with
any database. A database table is a table file that is
associated with a database. Database tables can have
properties that free tables do not have, such as field-level
and record-level rules, triggers, and persistent relationships.
Format Property
• Function: Specifies the input and output
formatting of a control's Value property.
Available at design time and run time.
• Syntax:
Control.Format[ = cFunction]
Return Value
•cFunction. Specifies the character constraints for
data entry and formatting for display. The
following table lists the valid cFunction values
for the appropriate controls.
cFunction
EditBox control
K
Description
Selects all the text when the control
gets focus.
cFunction
Description
Spinner control
$
Displays the currency symbol.
^
Displays numeric data using scientific notation.
K
Selects all the text when the control gets the
focus.
L
Displays leading zeros instead of spaces in the
text box.
cFunction
Description
Spinner control…
R
Displays the format mask for the text box that
is specified in the InputMask property.
The mask formats data for easier entry and
clearer display (for example, if the mask is 99999, the number 12345 is displayed as 12-345),
but is not stored as part of the data. Use only
with character or numeric data.
cFunction
Description
TextBox control and Column object
!
$
^
Converts alphabetic characters to uppercase.
Use with data of Character type only.
Displays the currency symbol. The
ControlSource property must specify a
numeric source for the text box.
Displays numeric data using scientific notation.
The ControlSource property must specify a
numeric source for the text box.
cFunction
Description
TextBox control and Column object …
A
D
E
F
Allows alphabetic characters only with no
spaces or punctuation marks.
Uses the current SET DATE format.
Edits Date values as British dates.
Prevents Varchar values from being padded
with trailing spaces in text boxes or Varbinary
values from being padded with trailing zeroes
(0s).
 Notes
• For text boxes bound to data with Varchar type, the
MaxLength property must be set to a nonzero value to
permit input for the desired number of characters.
• When you drag a field with Varchar type to a form, the
created text box's Format property is set to "F", and the
MaxLength property is set to the maximum length for
the Varchar field. When you drag a Grid control to a form
and create TextBox controls for columns with Varchar
type, the Format property is set to "F", and the
MaxLength property is set to the maximum length for
the Varchar field.
 Notes
• When you drag a field with Varbinary type to a form
or when you drag a Grid control to a form and create
TextBox controls for columns with Varbinary type,
the following occur:
Format property is set to "F".
MaxLength property is set to the maximum length
multiplied by 2 for the Varchar field.
InputMask property is filled with "H" up to the
value of the MaxLength property.
cFunction
Description
TextBox control and Column object …
K
Selects all the text when the control gets the
focus.
L
Displays leading zeros instead of spaces in the
text box. The ControlSource property must
specify a numeric source for the text box.
M
Included for backward compatibility.
cFunction
Description
TextBox control and Column object …
R
T
YS
YL
Displays the format mask for the text box that is specified in the InputMask
property. The mask formats data for easier entry and clearer display. For example, if
the mask is 99-999, the number 12345 is displayed as 12-345 but is not stored as
part of the data. Use only with Character or Numeric data.
Trims leading and trailing blanks from the input field.
Displays Date values in a short date format
determined by the Windows Control Panel short
date setting.
Displays Date values in a long date format determined
by the Windows Control Panel long date setting.
cFunction
Description
EditBox control, TextBox control, Column object, and
Spinner control
Z
Displays the value as blank if it is 0, except
when the control has focus.
Dates are also supported in these
controls. The / / date delimiters are not
displayed unless the control has focus.
Remarks
• Applies To: Column | ComboBox | EditBox | Spinner |
TextBox
• The Format property specifies a behavior for the entire
input field. You can mix several Format codes, but they
always affect everything in the input field. This property
contrasts to the InputMask property in which each
entry in the input mask corresponds to an entry in the
input field.
• The Format property mimics the behavior of the
FUNCTION clause in the @ ... GET and @ ... EDIT
commands
Table Creation
• Tables store data in a row and column format, similar to a
spreadsheet. Each row represents a record, and each
column represents the fields in each record. Tables in
Visual FoxPro can exist as a free table or as a database
table.
• A free table is a table (.dbf) file that is not associated with
any database. A database table is a table file that is
associated with a database. Database tables can have
properties that free tables do not have, such as field-level
and record-level rules, triggers, and persistent
relationships.
Table Creation…
• The following list includes some of the benefits
database tables offer:
Long names for the table and for each field in the table.
Captions and comments for each table field.
Default values, input masks, and format for table fields.
Default control class for table fields.
Field-level and record-level rules.
Primary key indexes and table relationships to support
referential integrity rules.
One trigger for each INSERT, UPDATE, or DELETE event.
Table Creation…
• However, free tables are useful for storing information
outside of a database. For example, for example, you
can use free tables to store lookup information that
multiple databases share. For more information about
the benefits of associating tables with a database, see
Databases in Visual FoxPro.
• To view a sample table, open one of the table (.dbf)
files for the Northwind database located in the Visual
FoxPro ...\Samples\Northwind directory. For more
information, see How to: View Records in Tables.
Considerations for Table Creation
• When creating tables, remember the following considerations:
Make sure field's data type matches the type of
information you want to store.
Make sure the field is wide enough to accommodate the
information it stores and displays.
Set an appropriate number of decimal places for Numeric
or Float fields.
Make sure that fields that can accept null values are
configured to accept them.
How to: View Records in Tables
•You can view the records in a table by
opening it in a browse window. A browse
window displays data in a table as rows
(records) and columns (fields) that you can
scroll through. For more information, see
Browse Window.
To browse data in a free table
1.
2.
On the File menu, click Open.
In the Open dialog box, browse to the
location of the table you want to view.
3. In the Files of type box, select the Table
(*.dbf) file type to display only table files.
4. Select the table file you want to view.
5. On the View menu, click Browse.
The table you selected opens in a browse
window.
To browse data in a database table
1. Open the database in the Database
Designer.
2. Select the table you want.
3. On the Database menu, click Browse.
The table opens in a browse window.
To browse data in a table from a project
1. Open the project in the Project Manager.
2. Expand the Data node and choose one of the following:
• To browse a database table, expand the Databases node,
then the Tables node.
-OR• To browse a free table, expand the Free Tables node.
3. Click the table you want to view, and then Browse.
The table you selected opens in a browse window.
To browse a table programmatically
1. Open the table with the USE command.
2. Follow USE with the BROWSE command.
 Tip:
To prevent users from adding records to a table while
browsing a table, include the NOAPPEND clause in the
BROWSE command.