The SET_META_EXIT method in NextTables for SAP BW

You will learn

What the SET_META_EXIT method of the Table Maintenance BAdI can change, how editability and visibility are expressed, and what every table and field parameter carries. The method controls the shape of the table: which columns a user sees, which of them can be edited, how a column searches for its values, and whether the table may be edited at all.

This article is for ABAP developers. It is the parameter reference; the settings it overrides are the ones described in Table and column configuration in NextTables for SAP BW.

Prerequisites

• A Table Maintenance BAdI implementation for your table. How to implement the table maintenance BAdI covers the enhancement spot, the implementing class and the filter values.
• ABAP development access on the BW system.

The method

The Table Maintenance BAdI's interface is /NLY/IF_BADI_EDITOR. It includes the component interface /NLY/IF_EDITOR, which carries the three exits. Metadata logic therefore runs in /NLY/IF_EDITOR~SET_META_EXIT of your implementing class.

The method runs before the table is rendered, so whatever it sets is what the user gets. It overrides the front-end configuration, which makes it the right place for rules that depend on who is logged in, on the time of year, or on data the configuration screen cannot see.

Editability: the three states

Every field is in one of three states, expressed by the EDITABLE property:

• 1 Locked. The user cannot change the value.
• 2 Editable and required. A value has to be entered; initial is refused.
• 3 Editable and not required. A value may be entered; initial is allowed.

Key fields behave differently on insert and on update. A key field may be filled when a row is created, but changing it later would not edit the row, it would create a different one. On an update event key fields are therefore always locked:

Required fields

By default key fields are required and non-key fields are not. Both defaults can be changed. A non-key field can be made required, for example a customer category that the business wants filled on every row. A key field can be made not required, for example when a semantic key spans several fields and one of them is allowed to stay initial.

Non-editable fields

Setting a field to locked stops the user changing it on edit or insert. The clearest case is a field the system fills for you, such as Changed by or Changed on: the value is written before the database update and must not be typed over by hand. How to track changes in NextTables for SAP BW shows that pattern end to end.

Table parameters

Properties of the table as a whole, in CH_S_TABLE_INFO:

Field parameters

Properties of a single column, in CH_T_FIELDS_INFO:

Search parameters

The F4HELP table of a field decides where its value help comes from and how it is presented:

Which of the three search modes to pick, and why most requirements never need CUSTOM, is covered in How to give editors the right values in NextTables for SAP BW.

Button parameters

The BUTTONS table of the table info defines custom buttons:

Custom buttons in NextTables for SAP BW explains the actions and what each one expects.

Step-by-Step Instructions

1. Loop over the fields and change what you need

The method hands you the field list as a changing parameter. Loop it, match on FNAME, and set the properties:

FIELD-SYMBOLS:
  <l_s_fields_info> TYPE /nly/ts_fields_info,
  <l_s_f4help>      TYPE /nly/ts_search_info.

* Change properties as needed
LOOP AT ch_t_fields_info ASSIGNING <l_s_fields_info>.

  CASE <l_s_fields_info>-fname.

    WHEN 'FIELD_NAME_1'.
      <l_s_fields_info>-editable = '1'.

    WHEN 'FIELD_NAME_2'.
      LOOP AT <l_s_fields_info>-f4help ASSIGNING <l_s_f4help>.
        <l_s_f4help>-searchstyle = 'DROPDOWN'.
      ENDLOOP.

  ENDCASE.

ENDLOOP.

2. Decide per event where the rule applies

Metadata is set once per table load, so a rule that should only apply while inserting has to test the context itself rather than rely on the event parameters the other two exits receive.

3. Report problems to the user

The method also receives CT_MESSAGES. If your logic refuses to build the table, say so instead of returning an empty grid. Error handling in the table maintenance BAdI for SAP BW covers the message and visual types.

Troubleshooting / FAQs