Indexed View Vs Indexes on Table

Indexed View vs Indexes on Table

An indexed view will cause the same issues as an index on the column, because indexed views require with schemabinding, which tie it to the table directly, disallowing you from changing/altering the schema of that table in any way, shape, or form. This includes resizing a column (e.g.-from varchar(50) to varchar(255)), changing a column's data type (e.g.-from double to decimal(18,5)), etc. I've seen them cause a lot of unexpected headaches due to this fact.

My suggestion is to set up a stored procedure or SSIS package that will create a reporting table for you that's run every hour or so. This way, you can index the ever-loving hell out of it and enjoy all the performance benefits that it produces. I shy against reporting from a live, in-progress system. I've actually yet to see the case where this is necessary. For reporting purposes, hour-old information is usually absolutely sufficient to get the job done.

What is difference between INDEX and VIEW in MySQL

VIEW

• View is a logical table. It is a physical object which stores data logically. View just refers to data that is tored in base tables.
• A view is a logical entity. It is a SQL statement stored in the database in the system tablespace. Data for a view is built in a table created by the database engine in the TEMP tablespace.

INDEX

• Indexes are pointres that maps to the physical address of data. So by using indexes data manipulation becomes faster.
• An index is a performance-tuning method of allowing faster retrieval of records. An index creates an entry for each value that appears in the indexed columns.

ANALOGY:

Suppose in a shop, assume you have multiple racks. Categorizing each rack based on the items saved is like creating an index. So, you would know where exactly to look for to find a particular item. This is indexing.

In the same shop, you want to know multiple data, say, the Products, inventory, Sales data and stuff as a consolidated report, then it can be compared to a view.

Hope this analogy explains when you have to use a view and when you have to use an index!

Indexed View vs. Table

What edition of SQL Server are you running under? Downlevel editions
require the use of the NOEXPAND query hint in order to benefit most
from the indexed view. – Damien_The_Unbeliever

This was the answer, thanks again

What is the difference between an table index and a view index?

There really is none. The index on both table or view basically serves to speed up searches.

The main thing is: views normally do not have indices. When you add a clustered index to a view, you're basically "materializing" that view into a system-maintained, always automatically updated "pseudo-table" that exists on disk, uses disk space just like a table, and since it's really almost a table already, you can also add additional indices to an indexed view.

So really - between a table and an indexed view, there's little difference - and there's virtually no difference at all between indices on tables and an indexed view.

In SQL Server, when should I use an indexed view instead of a real table?

You may want to use a view to simplify on queries. In our projects, the consensus is on using views for interfaces, and especially "report interfaces".

Imagine you've got a client table, and the manager wants a report every morning with the client's name, and their account balance (or whatever). If you code your report against the table, you're creating a strong link between your report and your table, making later changes difficult.

On the other hand if your report hits a view, you can twist the database freely; as long as the view is the same the report works, the manager is happy and you're free to experiment with the database. You want to separate client metadata from the main client table? go for it, and join the two tables in the view. You want to denormalize the cart info for the client? no problem, the view can adapt...

To be honest, it's my view as a programmer but other uses will certainly be found by db gurus :)

SQL Server: Filtered Indexes versus Indexed Views

An indexed view

• can include columns based on an expression.

• can include joins of multiple tables.

• can be referenced directly in user SQL statements.

• allows all deterministic expressions

• has complicated prerequisites, but is simple and consistent to use (select * from [indexedview])

A filtered index

• is limited to the columns contained within the table.

• only allows simple expressions for the filter.

• is simple to implement, but the optimizer will determine if usage is appropriate when the base table is queried.

Neither of them can use non-deterministic expressions.

Makes it sense to create an indexed view when the data is frequently changed?

This is not a definite answer, rather just some general ideas to consider.

An important piece of information is what indexes the 5 underlying tables have. If those indexes are helpful for the view, then the query optimizer would use them, thus an index on the view might not make the view faster.

Based on just the information you're giving us, the main questions are the business needs, which would help to determine your database architecture: how often the tables are updated, how often the view is queried, how fast the updates and view query need to perform, and how current the view data needs to be.

1. If the view query performance is more important than the speed of the table updates, then use an indexed view.

2. If the view data can be cached and not current, and if the table update speed is important, then you could periodically copy all of the table data into a reporting table, such as once per day or hour. On that reporting table, you could create an index for fast read querying.

3. If the view performance is not important, but that view data has to be current, and if table update speed is important, then you probably have to use a non-indexed view, and maybe rely on table scans for every view query.

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