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Avoid field names which may be used by database engines, or may match SQL types or keywords in any give database engine. Also note that some database engines require that field names begin with a letter. The following are some examples of problematic field names and some better suggestions: password (use passwd instead) length (use sizeLen instead) type (use typeCode instead) message (use messageText instead) year (use yearCode instead) limit (use maximum instead) date (use systemDateStamp instead) dateStamp (use systemDateStamp instead) time (use systemTimeStamp instead) timeStamp (use systemTimeStamp instead) class (use classCode instead) _1099Number (use vendor1099Number instead) Since each database engine is different, you have to be especially careful when naming fields. Field names which are fine on one database engine could clash with names of proprietary extensions in another database engine. Do not create field names which would match root field names of arrays after the removal of numeric subscripts. Here's an example: contactNote contactNote2 contactNote3 Note that contactNote2 and contactNote3 get converted to a Java array, named contactNote. That name clashes with the existing contactNote field (which is actually a separate Java variable) and causes a compiler error when trying to compile the entity bean. The correct way to do this would be: contactNote1 contactNote2 contactNote3 Also note that the same rules apply when the subscripts are embeddd within the names. The following would cause the same error: contactNote contact1Note contact2Note As would the following: contactNote1 contact1Note1 contact1Note2 contact2Note1 contact2Note2 Keep tables small, both in record size and in total number of fields. Most database engines can't handle huge records or records with several hundred fields. If you need more fields, create an additional table with the new fields and the same primary key fields as in the original table. You can easily look up the record in the new table only when you need it, as opposed to loading the new fields every time the original table is accessed. This will make the software run faster in general. After making even the SLIGHTEST change to ANY table's schema, test the entire system again on EVERY supported database engine. The minimum test should be to create an empty set of all tables in each supported database engine and check for any errors while creating the tables.