Categoria: ZIM 4GL Language Reference

Assigns a value to a variable object.

Syntax

LET expression

Parameters

Comments

The LET command is used to assign values to variable objects. To assign values to a field in an EntitySet or relationship, you must use ADD, CHANGE, INSERT, or UPDATE (which can contain a LET subcommand). The LET command is not used to assign values to database fields.

An assignment expression is formed by enclosing the LET command in parentheses.

If expression evaluates to $Null and target is a macro, the macro is assigned the null string. (A null string is a string of zero length, which is not the same as the $Null property.)

Example

let var1[1]=1 var1[2]=2 var1[3]=3

let var1 = $Date var2 = $tolower(LastName) var3[2] = 123

An example of using LET to assign values to variables.

let = “where LastName = Smith”

let= “from terminal prompt”

let <5> = $null

An example of using LET to assign values to macros.

See Also

Macros

ADD

CHANGE

How To Use Variables

INSERT

SET QUOTING

UPDATE

WHERE

Computes the results of one or more expressions for a set of records.

Syntax

COMPUTE [num] [setspec] EVALUATE clause [-> clause]

Parameters

Comments

COMPUTE evaluates one or more expressions for a set of records without having to first LIST the data or create a result set of the desired records.

Example

Compute all Employees where LName=Smith \

evaluate \

(let TotSal = $total(Salary)) \

(let MaxSal = $max(Salary)) \

(let MinSal = $min(Salary)) \

(let NoOfEmps = $count(LName)) \

(let AvgSal = $average (Salary))

output TotSal MaxSal MinSal NoOfEmps AvgSal

Processes the EVALUATE clause for every employee whose last name is “Smith”. The OUTPUT command displays the results.

form open dInvoice

form display input

compute fInvItems evaluate (let fInvBott.InvTot = $total(fInvItems.Amt))

form display fInvBott.InvTot

Calls up a display and calculates a total after all items have been added.

See Also

$MEMBERCOUNT

FIND

Gets serial input from the application user.

Syntax

INPUT «target»

Parameters

Comments

INPUT provides a simple means of reading a line of input from the application user. The line of input is divided into literal strings based on the delimiter character currently in effect. The literals are assigned to the variables and macros specified in target, in order from left to right.

Example

input TestVar fEmpform.LastName Param1 < CommandName> <3>

When the above command pauses for input, the following constants can be input by the application user:

32 Smith abc LIST abc_def

If current delimiter is the space character, the constants are assigned as follows:

The following sequence of entries accomplishes the same effect, but uses the comma as the delimiter:

set delimiter “,”

input TestVar fEmpform.LastName Param1 < CommandName> <3>

32,Smith, abc,LIST, abc_def

Attention

When using the following construction, a “:” must be placed at the end of the OUTPUT string:

OUTPUT “Please, respond with Yes or No (Y/N): “;

input vResponse

See Also

SET DELIMITER

OUTPUT

Moves the current member pointer one or more members down in a result set.

Syntax

DOWN [num] [setname]

Parameters

Comments

NEXT is a synonym for DOWN.

Example

down 10

Moves the current member pointer 10 members “down” towards the end of the set.

down 5

delete 5

Moves the current member pointer five members “down” and then deletes five members (starting with the new current member).

find Customers -> CustSet

form open fCustomer

form set accelerator F1 F2 Escape

while

 change fCustomer from CustSet

 form display input

 if Event.EventName = “escape”

  break

 else    % use $direction as a handy variable

  let $direction = {-1 where Event.EventName = “F1”, 1}

 endif

 down $direction CustSet

endwhile

Finds a set of customers and then displays the records in the set one at a time.

See Also

$currentmember

BOTTOM

DOWN

LOCATE

PREVIOUS

TOP

UP

Opens an application directory to use the objects contained in it.

Syntax

ACCESS dirname [READ|UPDATE]

Parameters

Comments

Initializing an application database (New Database) creates a base application directory called zim. Additional application directories are defined as objects in the application database. To access any directory other than the base application directory, you must issue an ACCESS command for that directory.

Once a directory has been accessed, objects in that directory are available for use. To close a directory (and its objects) to further access, use the RELEASE command.

Use the CREATE, ERASE, RENAME, PERMISSION, ENCRYPT, DECRYPT, COMPILE, UNCOMPILE, SET SIZE, and SET SELECTIVITY commands to change object definitions only in an application directory accessed using the UPDATE option.

By accessing a directory using the READ option, you prevent unwanted modification of the directory contents. Foreign directories can be accessed using READ only.

Example

To access directory ProjectControl in read-only mode, use

access ProjectControl read

or

access ProjectControl

To access the directory Personnel in update mode, use

access Personnel Update

See Also

$dirpath

COMPILE

CREATE

DECRYPT

ENCRYPT

ERASE

PERMISSION

RENAME

SET SELECTIVITY

SET SIZE

UNCOMPILE

UPDATE

Moves the current member pointer one or more members “down” in a result set.

Syntax

DOWN [num] [setname]

Parameters

Comments

NEXT is a synonym for DOWN.

Example

down 10

Moves the current member pointer 10 members “down” towards the end of the set.

down 5

delete 5

Moves the current member pointer five members “down” and then deletes five members (starting with the new current member).

find Customers -> CustSet

form open fCustomer

form set accelerator F1 F2 Escape

while

change fCustomer from CustSet

form display input

if Event.EventName = “escape”

break

else    % use $direction as a handy variable

let $direction = {-1 where Event.EventName = “F1”, 1}

endif

down $direction CustSet

endwhile

Finds a set of customers and then displays the records in the set one at a time.

See Also

$currentmember

BOTTOM

LOCATE

NEXT

PREVIOUS

TOP

UP

Locates a particular member of a result set and makes it the current member.

Syntax

LOCATE [num] [set] [WHERE clause]

Parameters

Comments

LOCATE starts searching at the current member of the set. The last member located becomes the current member of set. The system variable $Located is set to the number of members located, indicating the number of members in the result set.

The WHERE clause can be used to logically limit the members located.

Example

find all employees where location=”Detroit” -> DetroitSet

locate DetroitSet where FirstName=”John” and LastName=”Smith”

locate 2 DetroitSet where FirstName=”John” and LastName=”Smith”

Because LOCATE starts with the current member of any set it searches, the current member after the last LOCATE command is the third record containing the name John Smith.

find all Employees where LastName=”Smith” -> Smiths

locate all where FirstName=”John”

output $located

compute all Employees where LastName=”Smith” and FirstName=”John” valuate (“”)

output $membercount

find all Employees where LastName=”Smith” and FirstName=”John”

output $setcount

All three of the preceding examples determine how many employees have the name John Smith.

while

locate DetroitSet where LastName=”Smith” and FirstName=”John”

if $located = 0

  return    % checks if done

endif

ProcessEmp ( )  % program to process this John Smith

endwhile

Each John Smith record in the designated set is processed.

See Also

BOTTOM

DOWN

NEXT

PREVIOUS

TOP

UP

Ends execution of an application program and returns to the “previous” command level.

Syntax

RETURN [TO procedure]

Parameters

Comments

The RETURN command stops execution of the current procedure.

If a TO clause is omitted, execution control returns to the calling procedure (the “parent”) at the command immediately following the call that started execution of the current procedure.

If a TO clause is used, execution control returns to the specified procedure, provided that it is found along the chain of procedures that are “ancestors” of the current procedure. Execution resumes at the command immediately following the call that started execution of the offspring procedure in the current chain. If the specified procedure is not found along the chain of ancestors, execution control returns to the main prompt level.

If the RETURN command is entered at the main prompt level, the application session is ended (just as if a BYE command had been issued).

Example

To return control from the current procedure to the calling procedure when a FIND command returns an empty result set, enter

find all Employees where Salary > 10000

if $setcount = 0

 return

endif

To return to a grandparent procedure if a FIND command returns an empty result set, enter

01 procedure Grandparent ( )

02  Parent ( )        % goes to line 20

   … more commands …

18 endprocedure

19 %————————————————-

20 procedure Parent ( )

21  Child ( )        % goes to line 35

   … more commands …

33 endprocedure

34 %————————————————-

35 procedure Child ( )

36  find all Employees where Salary > 10000

37  if $setcount = 0

38    return to Grandparent  % goes to line 03

39  endif

   … more commands …

50 endprocedure

See Also

BYE

SET FLOW

STOP

TRANSACTION

TRANSFORM

Performs a Boolean AND of two logic expressions.

Syntax

expression1 AND expression2

Parameters

Return Value

Logical, as follows:

Comments

This AND is not the same as the AND used with the BETWEEN operator.

Example

ClaimType = ‘Auto’ and DamageCost > 3000 and LastName= ‘Andretti’

This Boolean expression is logically true only when the insurance claim type is Auto, the cost of the damage is greater than 3,000, and the last name of the person making the claim is Andretti. Otherwise, the Boolean expression is logically false.

See Also

[NOT] BETWEEN

NOT

XOR

OR

IN

Specifies the fields that are selected for a report

Syntax

DETAIL LINE [colheadings] [GRAPHIC [TEMPLATE name]] reportitem [:format:] [WHERE clause]

Parameters

Comments

The DETAIL LINE command is executed for every record of the set specified in the REPORT FROM command.

The column headings for all reportitems specified in the DETAIL LINE command are displayed, subject to any colheadings specification.

Only one detail line is produced for each record of the report set. If more than one DETAIL LINE command is used in a report specification, the DETAIL LINE command that is executed for a particular record in the report set is the first DETAIL LINE without a WHERE clause, or the first DETAIL LINE whose WHERE clause is true for that record.

For more information on format, see Available Format Options.

See Also

Boolean Expressions

Conditional Expressions

BREAK (Reports)

COLUMN BREAK

How to Use The Report Generator

How To Use Value Expressions