Loading from/to a Load Table
When using a load table to import or export data in a form load, it is recommended that the following steps be taken:
- Determine which form columns need to be loaded and into which forms. Pay special attention to mandatory columns that are not filled in automatically; these must be included in the load.
Determine how the interface will be structured. Choose between using the default GENERALLOAD table as your load table and designing your own table.
- If needed, you can add columns to the GENERALLOAD table.
- If you create your own table, in addition to the mandatory columns (see below), use column names that are relevant to the loaded data, as this will facilitate programming and interface definitions.
- Enter the needed data into the load table (e.g., build a program).
- Define the interface in the Form Load Designer. You may discover, as you define it, that you need to make adjustments to the load table. If you decide to switch load tables (e.g., create your own table), you will have to redefine the interface.
- Run the INTERFACE program.
The Load Table
Designate the name of the table in the Load Table column of the Form Load Designer form, indicating any Record Size.
The load table must contain certain columns, defined as follows (name, type, width, title):
- LINE (INT,8,'Ln')
- RECORDTYPE (CHAR,3,'Record Type')
- LOADED (CHAR,1,'Loaded?')
- KEY1 (CHAR,20,'Key 1')
- KEY2 (CHAR,20,'Key 2')
- KEY3 (CHAR,20,'Key 3')
The LINE column must be the unique key of the table.
- The predefined GENERALLOAD table meets all these criteria and also includes several columns of each type.
- The predefined GENERALLOAD_T also meets these criteria. Moreover, it contains an extra TITLE column, which can be used to store a message that will be added to the form's error message (if there is one). See, e.g., the DELWTASKITEMS procedure.
In some cases (see below) you may need more than three key columns. As you define the forms included in the load, the Form Load Designer will warn you if there are not enough keys in the designated table. If you need more keys, add them to the relevant GENERALLOAD table or design your own table.
Once a record is successfully loaded into a form (after the INTERFACE program is run), the LOADED column is assigned the value Y and the values of the key columns are updated by the new record that was opened. If there is an autounique key, that will serve as KEY1. If not, the columns making up the unique key will be inserted in as many keys as necessary. Therefore, you need at least as many key columns in your table as the number of columns in the unique key.
Example: If the INTERFACE program opens new customers, in every record that was successfully loaded into the CUSTOMERS form, the value in the KEY1 column will equal the value in the CUST column.
Forms in the Load
Use the Forms to be Loaded sub-level form to specify which forms participate in the load. These usually consist of a root form (e.g., ORDERS) and one or more sub-levels (e.g., ORDERITEMS).
Indicate the name of each form, as well as the code representing its record type. Each level in the form tree must be assigned its own unique record type (e.g., ORDERS = 1; ORDERITEMS = 2).
Tip: After recording a form, run the List of Sub-level Forms report by Action to view all its sub-levels (one level down only).
For each form, if you want the load to overwrite existing records in the sub-levels, flag the Replace Form Data column. Leave this column blank to add the new records to existing ones.
- Use of this flag to overwrite form data is based on the assumption that the existing record will be deleted successfully.
- If the form in question has a PRE-DELETE trigger, it is not advisable to flag this column, as the trigger may interfere with deletion.
- This flag is used mainly for text forms.
Link Form Columns to Table Columns
Use the next sub-level, Link Form Cols to Load Tbl Cols, to indicate which form columns are equivalent to which load table columns and to specify the order of column insertion.
While the Choose list of form columns only includes updatable columns in the form, the INTERFACE program can also insert values into hidden columns. This is useful, for instance, when you want to create a form load that updates records. Due so with caution, however. In most other cases, it is not good practice to insert values into hidden or read-only columns, as this may contradict some checks defined in the form.
Example: To update the unit price of ordered parts whose records already exist in the ORDERITEMS form, you would define one of the load table columns as updating the hidden ORDI column in that form. In this case, make this column first in order of insertion. But to specify the ordered part, use the PARTNAME column. ''Do not'' use the hidden PART column, even though this may seem easier, as the CHECK-FIELD trigger of the PARTNAME column will be bypassed and this is likely to have an adverse effect on record insertion.
If you want the INTERFACE program to treat empty strings and zero values as a true value, flag the Insert Null Values column.
Example: Flag this column to load records into the ORDERITEMS form for ordered parts with a unit price of 0. Otherwise, the INTERFACE program will ignore the 0 value in that column and insert the default unit price of the item instead by activating the form's trigger.
Adding Line Items to an Existing Document
When an interface that adds line items to a document is executed, by default the new items are inserted first in the document (that is, they receive a smaller line number than existing records). For instance, if a given interface adds lines to an existing order that contains two lines, the new record will appear on line 1, the first existing order item will move to line 2 and the second existing order item will move to line 3.
If you want to change the position of the new record (e.g., move it directly after the first line item), do the following:
- Define the interface so that existing lines are retrieved (e.g., by linking the INT1 column in the load table to the KLINE or ORDI column).
- Add a column to the load table to hold the internal ID of the first line (KLINE or ORDI).
- In the load table, insert the record of the new line to be added after the record that retrieves the first line.
Use the next sub-level, Default Value for Column, to assign a default value to be loaded into the form column. If the load table column is empty, the value specified in this sub-level form will be loaded into the form table. When the form load interface is used to export data, if the form column is empty, the default value will be exported.