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What is non-clustered index in Sybase?
nonclustered. means that the physical order of the rows is not the same as their indexed order. The leaf level of a nonclustered index contains pointers to rows on data pages. You can have as many as 249 nonclustered indexes per table. index_name.
Can we create primary key without clustered index?
The answer is NO. It is not possible at all. If I have to say in the most simple words, Primary Keys exists with either Clustered Index or Non-Clustered Index.
Is primary key always clustered?
Nope, it can be nonclustered. However, if you don’t explicitly define it as nonclustered and there is no clustered index on the table, it’ll be created as clustered. Show activity on this post.
Should primary key be clustered or nonclustered?
If you configure a PRIMARY KEY, Database Engine automatically creates a clustered index, unless a clustered index already exists. When you try to enforce a PRIMARY KEY constraint on an existing table and a clustered index already exists on that table, SQL Server enforces the primary key using a nonclustered index.
Should index keys be clustered or non-clustered?
If no, then the PK should be non-clustered. To give an example, consider a sales facts table. Each entry has an ID that is the primary key. But the vast majority of queries ask for data between a date and another date, therefore the best clustered index key would be the sales date, not the ID.
Should pk be clustered or non-clustered?
If yes, then the PK should be clustered. If no, then the PK should be non-clustered. To give an example, consider a sales facts table. Each entry has an ID that is the primary key.
What is an example of a clustered index?
Another example of having a different clustered index from the primary key is a very low selectivity key, like a ‘category’, or a ‘state’, a key with only very few distinct values.
What is the primary key unique constraint for PK_userid?
CONSTRAINT pk_UserID PRIMARY KEY (U_Id) Is the same as this one: CONSTRAINT pk_UserID PRIMARY KEY CLUSTERED (U_Id) You can only have the table data physicality ordered by one of the indexes, and by default that index is the one used for the primary key (the primary key unique constraint is always supported by an index).