Oracle

http://docs.oracle.com/cd/B19306_01/index.htm

Get schemas in DB

   1 SELECT DISTINCT USERNAME FROM DBA_USERS;

Get columns from table

   1 SELECT * FROM ALL_IND_COLUMNS WHERE TABLE_NAME='XYZ';

Get indexes from table

http://docs.oracle.com/cd/B19306_01/server.102/b14237/statviews_1069.htm

   1 SELECT index_name, table_owner, table_name, uniqueness FROM USER_INDEXES WHERE table_name = 'XYZ';
   2 SELECT index_name, table_owner, table_name, uniqueness FROM ALL_INDEXES WHERE table_name = 'XYZ';

Get code from stored procedure

   1 SELECT * FROM all_source WHERE name = 'myprocedure'
   2 ORDER BY owner,name,line

Show schema and table

   1 SELECT distinct owner,table_name 
   2 FROM all_tables
   3 ORDER BY owner,table_name;