Documentation: review Database Tables section

- Add missing entry for $g_db_table_suffix
- Add missing entry for $g_db_table_plugin_prefix
- Add warning about identifier size (Oracle 30-char limit)
- Remove obsolete information
- Rewording

Fixes #22221

docbook/Admin_Guide/en-US/config/database.xml

@@ -101,36 +101,60 @@
 		</varlistentry>
 	</variablelist>
 
-	<para>MantisBT enables users to configure a table prefix for all its
-		tables. This is useful to be able to have multiple MantisBT
-		installation in the same database. The advantage of that is for
-		users who are limited by their ISP to have one database.
+	<para>MantisBT allows administrators to configure a prefix and a suffix for
+		its tables. This is enables multiple MantisBT installation in the same
+		database or schema.
 	</para>
 
-	<variablelist>
+	<warning>
+		<para>Use of long strings for these configuration options may cause
+			issues on RDBMS restricting the size of its identifiers, such as
+			Oracle (which imposed a maximum size of 30 characters until version
+			12.1; starting with 12cR2 this
+			<ulink url="http://docs.oracle.com/database/122/SQLRF/Database-Object-Names-and-Qualifiers.htm#SQLRF51129">
+				limit has been increased to 128</ulink>).
+		</para>
+	</warning>
 
+	<variablelist>
 		<varlistentry>
 			<term>$g_db_table_prefix</term>
 			<listitem>
-				<para>Specifies the prefix to be use for all table names. The
-					default value is 'mantis'. If you override the default prefix, make
-					sure to update doc/db_generate.sql file before generating your
-					database. The other option is to import db_generate.sql as is, then
-					rename the tables to match the new prefix.
+				<para>Specifies the prefix to be used for all table names.
+					The default value is 'mantis'.
 				</para>
+				<para>The prefix can be used to help make sure table names are unique.
+					This is useful for users who are limited to a single database
+					or schema.
+				</para>
+			</listitem>
+		</varlistentry>
 
-				<para>The prefix is used to help make sure table names are unique.
+		<varlistentry>
+			<term>$g_db_table_suffix</term>
+			<listitem>
+				<para>Specifies the prefix to be appended to all table names.
+					The default value is 'table'.
+				</para>
+				<para>The suffix can be used to help make sure table names are unique.
 					This is useful for users who are limited to one database.
 				</para>
-				<note><para>
-						The table name for each of the tables is stored in a variable which
-						is calculated based on this configuration option. If you change the
-						prefix you have to make sure these variables are re-calculated (by
-						adding these calculation statements to config_inc.php after
-						assigning the new prefix). An example of these variables is:
-						$g_mantis_bug_file_table
-					</para>
-				</note>
+			</listitem>
+		</varlistentry>
+
+		<varlistentry>
+			<term>$g_db_table_plugin_prefix</term>
+			<listitem>
+				<para>Specifies the prefix to be used to differentiate tables
+					belonging to a plugin's schema from MantisBT's base tables.
+					The default value is 'plugin'.
+				</para>
+				<para>Plugin table names are built using the plugin's
+					<emphasis>basename</emphasis>, e.g. for a table named 'foo'
+					in the 'Example' plugin (with default values for prefixes
+					and suffix), the physical table name would be
+					<literal>mantis_plugin_Example_foo_table</literal>.
+				</para>
 			</listitem>
 		</varlistentry>
 	</variablelist>