SQL Server - Maximum Sizes

Object	Maximum sizes/numbers	Maximum sizes/numbers	Maximum sizes/numbers
	SQL Server 7 (32-bit)	SQL Server 2000 (32-bit)	SQL Server 2005 (32-bit)
Batch size	65,536 * Network Packet Size	65,536 * Network Packet Size	65,536 * Network Packet Size
Bytes per short string column	8000	8000	8000
Bytes per text, ntext, image, varchar(max), nvarchar(max), varbinary(max), or XML column	231 -2 bytes/p>	231 -2 bytes/p>	231 -1 bytes/p>
Bytes per GROUP BY, ORDER BY	8060	8060	8060
Bytes per index	900	900	9001
Bytes per foreign key	900	900	??2
Bytes per primary key	900	900	900 - Not listed, but since this will be an index, the index guidelines should apply.
Bytes per row	8060	8060	8060
Bytes in source text of a stored procedure	Lesser of batch size or 250 MB or 128MB3	Lesser of batch size or 250 MB or 128MB3	128MB
Clustered indexes per table	1	1	1
Columns in GROUP BY, ORDER BY	Limited only by number of bytes	Limited only by number of bytes	Limited only by number of bytes
Columns or expressions in a GROUP BY WITH CUBE or WITH ROLLUP statement	10	10	10
Columns per index	16	16	164 5
Columns per foreign key	16	16	164
Columns per primary key	16	16	164
Columns per base table	1024	1024	1024
Columns per SELECT statement	4096	4096	4096
Columns per INSERT statement	1024	1024	1024
Connections per client	Maximum value of configured connections (32,767 max)	Maximum value of configured connections (32,767 max)	Maximum value of configured connections (32,767 max)
Database size	1,048,516 terabytes	1,048,516 terabytes	1,048,516 terabytes
Databases per instance of SQL Server	32767	32767	32767
Filegroups per database	256	256	32767
Files per database	32767	32767	32767
File size (data)	32 terabytes	32 terabytes	32 terabytes
File size (log)	32 terabytes	32 terabytes	32 terabytes
Foreign key table references per table	253	253	253
Identifier length (in characters)	128	128	128
Instances per computer	16	16	50
Length of a string containing SQL statements (batch size)	65,536 * Network packet size	65,536 * Network packet size	65,536 * Network packet size
Locks per connection	Maximum locks per server	Maximum locks per server	Maximum locks per server
Locks per instance of SQL Server	Up to 2,147,483,647	Limited only by memory	Limited to 60% of memory
Nested stored procedure levels	32	32	32
Nested subqueries	32	32	no limit, at least according to Beta 2 BOL
Nested trigger levels	32	32	32
Nonclustered indexes per table	249	249	249
Objects concurrently open in an instance of SQL Server	2,147,483,647 per database (depending on available memory)	2,147,483,647 per database (depending on available memory)	2,147,483,647 per database (depending on available memory)
Objects in a database	2147483647	2147483647	2147483647
Parameters per stored procedure	2100	2100	2100
Parameters per user-defined function	2100	2100	2100
REFERENCES per table	253	253	253
Rows per table	Limited by available storage	Limited by available storage	Limited by available storage
Tables per database	Limited by number of objects in a database	Limited by number of objects in a database	Limited by number of objects in a database
Tables per SELECT statement	256	256	256
Triggers per table	Limited by number of objects in a database	Limited by number of objects in a database	Limited by number of objects in a database
UNIQUE indexes or constraints per table	249 nonclustered and 1 clustered	249 nonclustered and 1 clustered	249 nonclustered and 1 clustered
Footnotes
1 - By including nonkey columns in the index, you can exceed the 900 byte limit as these columns (used in covering queries) are not computed as part of the 900 byte limit.
2 - I could not find this listed in the SQL Server 2005 Beta 2 BOL.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/architec/8_ar_ts_8dbn.asp" title="'>http://msdn.microsoft.com/library/default.asp?url=/library/en-us/architec/8_ar_ts_8dbn.asp"> 3 - The Maximum Capacity Specifications shows the less or the batch size or 250MB, however Books Online shows 128MB in the entry for
4 - The 16 column limit is for key columns. Additional columns can be included (as in footnote 1) beyond the 15.
5 - Not valid for XML indexes.