Tables

Table Names

The following rules apply to table names:

  • They are restricted to 20 characters.
  • They may only contain alphanumeric values and the underline sign (no spaces).
  • They must begin with a letter.
  • You may not use a reserved word (a list of reserved words appears in the Reserved Words form — System Management → Dictionaries).
  • The name of any new table (one you have added yourself) must begin with a four-letter prefix (e.g., XXXX_CUSTOMERS). All tables (and any other Priority entities) that you have created for the same customer should share the same prefix.

Table Type

The table type determines whether the table is an application table or a system table. An application table is a table in which data is maintained separately for each Priority company, whereas a system table is used to store data that is common to all companies in the current Priority installation.

For historical reasons,Priority lists 4 possible values in the TYPE column:

  • 0/1 – for application tables
  • 2/3 – for system tables

However, new tables should always be assigned type 0.

Note: You cannot create new system tables or add new columns to system tables.

Rules for Modifying Tables and Table Columns

  1. When modifying tables, do not change standard table columns or any of the table’s unique (or Auto Unique) keys.
  2. If you add a column to the table, the column name must begin with a four-letter prefix. Use the same prefix for all table columns (as well as any other Priority entities) that you have added for a given customer.
  3. When creating a new table, the table name should begin with the appropriate four-letter prefix (there is no need to add this prefix to the new table’s columns).

When Installing a Revision with Modifications of a Standard Table

  • Ensure that all users have exited the system.

Note: For general guidelines for development, see Working with Version Revisions.

Further Reading