What is System Databases?

SQL Server includes the following system databases.

System database	Description
master Database	Records all the system-level information for an instance of SQL Server.
msdb Database	Is used by SQL Server Agent for scheduling alerts and jobs.
model Database	Is used as the template for all databases created on the instance of SQL Server. Modifications made to the model database, such as database size, collation, recovery model, and other database options, are applied to any databases created afterward.
Resource Database	Is a read-only database that contains system objects that are included with SQL Server. System objects are physically persisted in the Resource database, but they logically appear in the sys schema of every database.
tempdb Database	Is a workspace for holding temporary objects or intermediate result sets.

2. The SQL Data Types

The columns named 8, 9, 10 and 11 indicates SQL Server version data type support where

• 8 = SQL Server 2000
• 9 = SQL Server 2005
• 10 = SQL Server 2008
• 11 = SQL Server 2012

DATATYPE	MIN	MAX	STORAGE	8	9	10	11	TYPE	NOTES
Bigint	-2^63	2^63-1	8 bytes					Exact
Int	-2,147,483,648	2,147,483,647	4 bytes					Exact
Smallint	-32,768	32,767	2 bytes					Exact
Tinyint	0	255	1 bytes					Exact
Bit	0	1	1 to 8 bit columns in the same table requires a total of 1 byte, 9 to 16 bits = 2 bytes, etc...					Exact
Decimal	-10^38+1	10^38–1	Precision 1-9 = 5 bytes, precision 10-19 = 9 bytes, precision 20-28 = 13 bytes, precision 29-38 = 17 bytes					Exact	The Decimal and the Numeric data type is exactly the same. Precision is the total number of digits. Scale is the number of decimals. For both the minimum is 1 and the maximum is 38.
Numeric	same as Decimal	same as Decimal	same as Decimal					Exact
Money	-2^63 / 10000	2^63-1 / 10000	8 bytes					Exact
Smallmoney	-214,748.3648	214,748.3647	4 bytes					Exact
Float	-1.79E + 308	1.79E + 308	4 bytes when precision is less than 25 and 8 bytes when precision is 25 through 53					Approx	Precision is specified from 1 to 53.
Real	-3.40E + 38	3.40E + 38	4 bytes					Approx	Precision is fixed to 7.
Datetime	1753-01-01 00:00:00.000	9999-12-31 23:59:59.997	8 bytes					Datetime	If you are running SQL Server 2008 or later and need milliseconds precision, use datetime2(3) instead to save 1 byte.
Smalldatetime	1900-01-01 00:00	2079-06-06 23:59						Datetime
Date	0001-01-01	9999-12-31	3 bytes	no	no			Datetime
Time	00:00:00.0000000	23:59:59.9999999		no	no			Datetime	Specifying the precision is possible. TIME(3) will have milliseconds precision. TIME(7) is the highest and the default precision. Casting values to a lower precision will round the value.
Datetime2	0001-01-01 00:00:00.0000000	9999-12-31 23:59:59.9999999	Presicion 1-2 = 6 bytes precision 3-4 = 7 bytes precision 5-7 = 8 bytes	no	no			Datetime	Combines the date datatype and the time datatype into one. The precision logic is the same as for the time datatype.
Datetimeoffset	0001-01-01 00:00:00.0000000 -14:00	9999-12-31 23:59:59.9999999 +14:00	Presicion 1-2 = 8 bytes precision 3-4 = 9 bytes precision 5-7 = 10 bytes	no	no			Datetime	Is a datetime2 datatype with the UTC offset appended.
Char	0 chars	8000 chars	Defined width					String	Fixed width
Varchar	0 chars	8000 chars	2 bytes + number of chars					String	Variable width
Varchar(max)	0 chars	2^31 chars	2 bytes + number of chars	no				String	Variable width
Text	0 chars	2,147,483,647 chars	4 bytes + number of chars					String	Variable width
Nchar	0 chars	4000 chars	Defined width x 2					Unicode	Fixed width
Nvarchar	0 chars	4000 chars						Unicode	Variable width
Nvarchar(max)	0 chars	2^30 chars		no				Unicode	Variable width
Ntext	0 chars	1,073,741,823 chars						Unicode	Variable width
Binary	0 bytes	8000 bytes						Binary	Fixed width
Varbinary	0 bytes	8000 bytes						Binary	Variable width
Varbinary(max)	0 bytes	2^31 bytes		no				Binary	Variable width
Image	0 bytes	2,147,483,647 bytes						Binary	Variable width. Prefer to use the varbinary(max) type as the image type will be removed in future versions.
Sql_variant								Other	Stores values of various SQL Server-supported data types, except text, ntext, and timestamp.
Timestamp								Other	Stores a database-wide unique number that gets updated every time a row gets updated.
Uniqueidentifier								Other	Stores a globally unique identifier (GUID).
Xml				no				Other	Stores XML data. You can store xml instances in a column or a variable.
Cursor								Other	A reference to a cursor.
Table								Other	Stores a result set for later processing.