SELECT t.name AS 'table', i.name AS 'index', it.xtype,
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 1
AND k.id = t.id)
AS 'column1',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 2
AND k.id = t.id)
AS 'column2',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 3
AND k.id = t.id)
AS 'column3',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 4
AND k.id = t.id)
AS 'column4',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 5
AND k.id = t.id)
AS 'column5',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 6
AND k.id = t.id)
AS 'column6',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 7
AND k.id = t.id)
AS 'column7',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 8
AND k.id = t.id)
AS 'column8',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 9
AND k.id = t.id)
AS 'column9',
(SELECT c.name FROM syscolumns c INNER JOIN sysindexkeys k
ON k.indid = i.indid
AND c.colid = k.colid
AND c.id = t.id
AND k.keyno = 10
AND k.id = t.id)
AS 'column10',
FROM sysobjects t
INNER JOIN sysindexes i ON i.id = t.id
INNER JOIN sysobjects it ON it.parent_obj = t.id AND it.name = i.name
WHERE it.xtype = 'PK'
ORDER BY t.name, i.name
It is a convenient way to make instance methods into class methods. But you can also use it as a more efficient singleton.
In a module, self is the module class itself. So for example
puts self
will return Rake so,
extend self
basically makes the instance methods defined in Rake available to it, so you can do
Rake.run_tests