Database Details

sSQL Server Database Engine object Maximum sizes/numbers SQL Server (32-bit) Maximum sizes/numbers SQL Server (64-bit)
Batch size1 65,536 * Network Packet Size 65,536 * Network Packet Size
Bytes per short string column 8,000 8,000
Bytes per GROUP BY, ORDER BY 8,060 8,060
Bytes per index key2 900 900
Bytes per foreign key 900 900
Bytes per primary key 900 900
Bytes per row8 8,060 8,060
Bytes in source text of a stored procedure Lesser of batch size or 250 MB Lesser of batch size or 250 MB
Bytes per varchar(max), varbinary(max), xml, text, or image column 2^31-1 2^31-1
Characters per ntext or nvarchar(max) column 2^30-1 2^30-1
Clustered indexes per table 1 1
Columns in GROUP BY, ORDER BY 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
Columns per index key7 16 16
Columns per foreign key 16 16
Columns per primary key 16 16
Columns per nonwide table 1,024 1,024
Columns per wide table 30,000 30,000
Columns per SELECT statement 4,096 4,096
Columns per INSERT statement 4096 4096
Connections per client Maximum value of configured connections Maximum value of configured connections
Database size 524,272 terabytes 524,272 terabytes
Databases per instance of SQL Server 32,767 32,767
Filegroups per database 32,767 32,767
Files per database 32,767 32,767
File size (data) 16 terabytes 16 terabytes
File size (log) 2 terabytes 2 terabytes
Foreign key table references per table4 253 253
Identifier length (in characters) 128 128
Instances per computer 50 instances on a stand-alone server for all SQL Server editions.
SQL Server supports 25 instances on a failover cluster.
50 instances on a stand-alone server.
25 instances on a failover cluster.
Length of a string containing SQL statements (batch size)1 65,536 * Network packet size 65,536 * Network packet size
Locks per connection Maximum locks per server Maximum locks per server
Locks per instance of SQL Server5 Up to 2,147,483,647 Limited only by memory
Nested stored procedure levels6 32 32
Nested subqueries 32 32
Nested trigger levels 32 32
Nonclustered indexes per table 999 999
Number of distinct expressions in the GROUP BY clause when any of the following are present: CUBE, ROLLUP, GROUPING SETS, WITH CUBE, WITH ROLLUP 32 32
Number of grouping sets generated by operators in the GROUP BY clause 4,096 4,096
Parameters per stored procedure 2,100 2,100
Parameters per user-defined function 2,100 2,100
REFERENCES per table 253 253
Rows per table Limited by available storage Limited by available storage
Tables per database3 Limited by number of objects in a database Limited by number of objects in a database
Partitions per partitioned table or index 1,000 1,000
Statistics on non-indexed columns 30,000 30,000
Tables per SELECT statement Limited only by available resources Limited only by available resources
Triggers per table3 Limited by number of objects in a database Limited by number of objects in a database
Columns per UPDATE statement (Wide Tables) 4096 4096
User connections 32,767 32,767
XML indexes

http://msdn.microsoft.com/en-us/library/ms143432.aspx
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