This version of the SELECT statement was the only way to join tables until SAP release 3.0E.  It is recommended that the SQL JOIN be used.  However, this is an alternate method of joining tables that may be used in some circumstances.  Remember, SQL JOIN doesn’t utilize the SAP internal database buffer.

1. The driver table cannot be empty. This would cause one full table scan.
2. In general, keep the driver table as small and unique (in regards to the fields that would be needed for referencing in the FAEI) as possible. If duplicate entries are not deleted, identical data is read unnecessarily from the database.
3. If FAEI is used, the selected field list must be a superset of all the key fields of the database tables used in SQL. This is absolutely required to avoid data loss since the DB interface in R/3 returns unique sets of the result set to the application program. Failing to ensure this may cause problems when you want to get all records from a database table that match a certain condition.
4. Avoid using FAEI on a small DB table (like configuration tables). This could potentially cause full table scans for each FAEI packet. Even if it does index range scan, it is better to get data from the small DB tables by individual SELECT without the use of FAE.
5. Always use FAEI in conjunction with a DB index otherwise it would cause multiple full table scans (one table scan for each FAEI packet).
6. The first field(s) of the DB index should refer to the fields of the FAEI driver table in the SQL WHERE clause. Do not leave gaps between index fields in the WHERE clause. Inefficient index access will impact every FAEI packets.
7. FAEI works best when retrieving a small percentage of data from a Database table. When a large percentage of data is needed, consider getting data out of the DB table without FAEI implementation, and then do additional filtration in your application.

Related Items:

• Accessing data in Packages
• Describe Select-Options
• Displaying an IDoc in a report
• Dynamic selection screen based
• Dynamic selection screens