Differences between xtype and type in the SQL Server System Table sysobjects

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Each object created by sysobjects in the database (constraints, default values, logs, rules, stored procedures, etc.) occupies one row in the table. Only TempdbEach temporary object occupies a row in the table.

Sysobjects has two fields (type and xtype) that indicate the object type ).

Type exists in SQL Server 6.0 and xtype exists in SQL Server 7.0.

The differences between type and xtype are as follows:
Type:
K = primary key or unique constraint
R = rule

Xtype:
PK = primary key constraint (type: K)
Uq = unique constraint (type is K)

Type exists to be compatible with previous versions. You can use xtype after SQL Server7.0.