Record input / Usage |
The INPUT instruction binds program variables (typically, members of a RECORD) are bound to the fields of a screen record of the current form, and synchronizes the data between field input buffers and program variables.
SCHEMA stock DEFINE custrec RECORD LIKE customer.* ... INPUT BY NAME custrec.* ... END INPUT
The INPUT variable-list FROM field-list clause explicitly binds the variables to form fields by position. The form can include other fields that are not part of the specified variable list, but the number of variables or record members must equal the number of form fields listed in the FROM clause. Each variable must be of the same (or a compatible) data type as the corresponding form field. When the user enters data, the runtime system checks the entered value against the data type of the variable, not the data type of the form field.
SCHEMA stock DEFINE custrec RECORD LIKE customer.*, comment VARCHAR(100) ... INPUT custrec.*, comment FROM sr_cust.*, cmt ... END INPUT
When using the FROM clause with a screen record followed by a .* (dot star), keep in mind that program variables are bound to screen record fields by position, so you must make sure that the program variables are defined (or listed) in the same order as the screen array fields.
The program variables can be of any data type: The runtime system will adapt input and display rules to the variable type. If a variable is declared with the LIKE clause and uses a column defined as SERIAL / SERIAL8 / BIGSERIAL, the runtime system will treat the field as if it was defined with the NOENTRY attribute in the form file: Since values of serial columns are automatically generated by the database server, no user input is required for such fields.
INPUT p_items.* FROM s_items.* ATTRIBUTES ( UNBUFFERED ) ON CHANGE code IF p_items.code = "A34" THEN LET p_items.desc = "Item A34" END IF END INPUT
When the INPUT instruction executes, any column default values are displayed in the screen fields, unless you specify the WITHOUT DEFAULTS keywords. The column default values are specified in the form specification file with the DEFAULT attribute, or in the database schema files.
LET p_items.code = "A34" INPUT p_items.* FROM s_items.* WITHOUT DEFAULTS BEFORE INPUT MESSAGE "You should see A34 in field 'code'..." END INPUT
If the program record has the same structure as a database table (this is the case when the record is defined with a LIKE clause), you may not want to display/use some of the columns. You can achieve this by used PHANTOM fields in the screen record definition. Phantom fields will only be used to bind program variables, and will not be transmitted to the front-end for display.