Syntax of CONSTRUCT instruction

The CONSTRUCT instruction provides database query by example, producing a WHERE condition for SELECT.

Syntax 1: Implicit field-to-column mapping

CONSTRUCT BY NAME variable ON column-list
    [ ATTRIBUTES ( { display-attribute
                     | control-attribute }
                     [,...] ) ]
    [ HELP help-number ]
[ dialog-control-block
  [...] 
END CONSTRUCT ]

Syntax 2: Explicit field-to-column mapping

CONSTRUCT variable ON column-list FROM field-list
    [ ATTRIBUTES ( { display-attribute
                     | control-attribute
                     } [,...] ) ]
    [ HELP help-number ]
[ dialog-control-block
   [...] 
END CONSTRUCT ]

where column-list defines a list of database columns as:

{ column-name
| table-name.*
|  table-name. column-name
} [,...]

where field-list defines a list of fields with one or more of:

{ field-name
| table-name.*
| table-name.field-name
| screen-array[line].*
| screen-array[line].field-name
| screen-record.*
| screen-record.field-name
} [,...]

where dialog-control-block is one of:

{ BEFORE CONSTRUCT
| AFTER CONSTRUCT
| BEFORE FIELD field-spec [,...]
| AFTER FIELD field-spec [,...]
| ON IDLE idle-seconds
| ON ACTION action-name [INFIELD field-spec]
| ON KEY ( key-name [,...] )
}
    dialog-statement
    [...]

where dialog-statement is one of:

{ statement
| NEXT FIELD { NEXT | PREVIOUS | field-spec}
| CONTINUE CONSTRUCT
| EXIT CONSTRUCT 
}

where field-spec identifies a unique field with one of:

{ field-name
| table-name.field-name
| screen-array.field-name
| screen-record.field-name
}

where display-attribute is:

{ BLACK | BLUE | CYAN | GREEN
| MAGENTA | RED | WHITE | YELLOW
| BOLD | DIM | INVISIBLE | NORMAL
| REVERSE | BLINK | UNDERLINE
}

where control-attribute is:

{ ACCEPT [ = boolean ]
| CANCEL [ = boolean ]
| FIELD ORDER FORM
| HELP = help-number
| NAME = "dialog-name"
}

variable is the variable that will contain the SQL condition built by the CONSTRUCT instruction.
column-name is the identifier of a database column of the current form.
table-name is the identifier of a database table of the current form.
field-name is the identifier of a field of the current form.
screen-array is the screen array that will be used in the current form.
line is a screen array line in the form.
screen-record is the identifier of a screen record of the current form.
help-number is an integer that allows you to associate a help message number with the instruction.
key-name is a hot-key identifier (like F11 or Control-z).
dialog-name is the identifier of the dialog.
action-name identifies an action that can be executed by the user.
idle-seconds is an integer literal or variable that defines a number of seconds.
statement is any instruction supported by the language.

The ON clause defines the list of form fields in which the user can enter search criteria. The BY NAME keyword implicitly maps form fields to the database columns listed in the ON clause. Use the FROM field-list clause if you need to map form fields to database columns explicitly, when the column and field names do not match.