What is the difference between select and parameters?
The difference between parameters and select options are as follows:1.The main difference between parameters and select options lies in the data selection. In case of a parameter, if the selection screen field is left blank, then no data is selected on the other hand if the select option is left blank then, all the data from db is selected. 2. Another difference is that parameter acts as a variable whereas select option acts as an internal table with a predefined structure.
3. At parameter variable you can specify only single value but you can specify more than one input values in a variable specified with select-options, when you declare select-options a selection tables like Internal table with 4 fields like SIGN,OPTION,LOW and High gets created to store the multiple values that are entered in the select -options.
4.The main diffrence between select-options and parametrs is, select-options gives us a range of selections but in parameter we can't do that we can declare parameters as radio button and checkboxes but for select-options we can't.
The main difference between select-options and parameters is that the select-option creates a selection table consisting of 4 fields.
Please go thru the following details to learn more bout it...
Description of the individual components:
The data type of SIGN is C with length 1. The contents of SIGN determine for each row whether the result of the row condition is to be included in or excluded from the resulting set of all rows.
Possible values are I and E.
– I stands for "inclusive" (inclusion criterion - operators are not inverted)
– E stands for "exclusive" (exclusion criterion - operators are inverted)
The data type of OPTION is C with length 2. OPTION contains the selection operator. The following operators are available:
– If HIGH is empty, you can use EQ, NE, GT, LE, LT,CP, and NP. These operators are the same as those that are used for logical expressions. Yet operators CP and NP do not have the full functional scope they have in normal logical expressions. They are only allowed if wildcards ( '*' or '+' ) are used in the input fields.
If wildcards are entered on the selection screen, the system automatically uses the operator CP. The escape character is defined as #.
– If HIGH is filled, you can use BT (BeTween) and NB (Not Between). These operators correspond to BETWEEN and NOT BETWEEN that you use when you check if a field belongs to a range. You cannot use wildcard characters.
The data type of LOW is the same as the column type of the database table, to which the selection criterion is linked.
– If HIGH is empty, the contents of LOW define a single field comparison. In combination with the operator in OPTION, it specifies a condition for the database selection.
– If HIGH is filled, the contents of LOW and HIGH specify the upper and lower limits for a range. In combination with the operator in OPTION, the range specifies a condition for the database selection.
The data type of HIGH is the same as the column type of the database table, to which the selection criterion is linked. The contents of HIGH specify the upper limit for a range selection.
The parameter statement does not create a selection table .
The second thing is select-option gives us a range for selection, whereas parameter doesn't .
Using the parameter you can define radio buttons and checkboxes where as select-options can't.