Microsoft SQL Server
A few useful tidbits
--- Table description
SELECT * FROM ::fn_listextendedproperty (NULL, 'user', 'dbo', 'table', 'tableNameHere', NULL, NULL)
-- Field descriptions
SELECT * FROM ::fn_listextendedproperty (NULL, 'user', 'dbo', 'table', 'tableNameHere', 'column', NULL) WHERE name = 'MS_Description'
-- If you need to search for tables containing a specific field:
SELECT object_name(id), name
FROM syscolumns
WHERE name LIKE '%field%'
AND id IN (SELECT id FROM sysobjects WHERE type ='u')