Since SQL Server 2008 R2, Microsoft offers an alternative solution to indexed views called filtered indices. Filtered indices are a special form of nonclustered indices, where the index is narrowed using a condition in the particular query. Using a filtered index has several advantages over using an indexed view. In that case SQL Server will choose in the execution plan a Clustered Index Seek operator. Seek operations are very, very efficient, because SQL Server uses a B-tree structure to find the relevant data. A Non-Clustered Index you will use alongside a clustered index to improve read performance. You should put these on columns used in WHERE Clause, JOIN, etc and can include other columns that the query needs, to enhance performance even more. This is called a "covering index". So, in a nutshell, it is not the case of one being better than the other.

Find out the advantages and disadvantages of SQL indexing from the experts at Global Knowledge. The real value of indexing is to help retrieve data quickly, but you must consider the negative impact on the server when data is modified. Disadvantages of the Indexes. - Every time data changes in the table, all the indexes need to be updated. - Indexes need disk space. The more indexes you have, more disk space is used. - Index decreases the performance on inserts, updates and deletes. - It slows down the query performance. The ratio of index size to table size can vary greatly, depending on the columns, data types, and number of indexes on a table. Indexes and Data Modification Another downside to using an index is the performance implication on data modification statements. An index is associated with tables or table cluster that can speed data access and reducing disk I/O. By creating an index, You can retrieve related set of rows from table instead of All Rows. In database technologies (Oracle, SQL Server, Sybase, DB2, MySQL, PostreSQL, etc.), One index on a table is not a big deal. You automatically have an index on columns (or combinations of columns) that are primary keys or declared as unique. There is some overhead to an index. The index itself occupies space on disk and memory (when used). So, if space or memory are issues then too many indexes could be a problem. Since SQL Server 2008 R2, Microsoft offers an alternative solution to indexed views called filtered indices. Filtered indices are a special form of nonclustered indices, where the index is narrowed using a condition in the particular query. Using a filtered index has several advantages over using an indexed view. In that case SQL Server will choose in the execution plan a Clustered Index Seek operator. Seek operations are very, very efficient, because SQL Server uses a B-tree structure to find the relevant data.

So far we have only discussed query performance, but SQL is not only about queries. It supports data manipulation as well. The respective commands— insert  

SQL is used as their standard database language by all the relational database management systems like Oracle, Informix, Posgres, SQL server, MySQL, MS Access, and Sybase. Also See: Characteristics of Database Approach. What is SQL, its Applications, Advantages and Disadvantages? History about SQL. In the 1970s, SQL was developed by the Raymond FF. An index is associated with tables or table cluster that can speed data access and reducing disk I/O. By creating an index, You can retrieve related set of rows from table instead of All Rows. In database technologies (Oracle, SQL Server, Sybase, DB2, MySQL, PostreSQL, etc.), Disadvantages of SQL. Along with some benefits, the Structured query language also has some certain disadvantages: Difficult Interface; SQL has a complex interface that makes it difficult for some users to access it. Partial Control; The programmers who use SQL doesn’t have a full control over the database because of the hidden business rules. The cost of an index in disk space is generally trivial. The cost of additional writes to update the index when the table changes is often moderate. The cost in additional locking can be severe. It depends on the read vs write ratio on the table, and on how often the index is actually used to speed up a query.

Another way to identify non-indexed columns to add statistics to is to use the Index Wizard. It can identify columns that can benefit from column statistics, and add 

Disadvantages of the Indexes. - Every time data changes in the table, all the indexes need to be updated. - Indexes need disk space. The more indexes you have, more disk space is used. - Index decreases the performance on inserts, updates and deletes. - It slows down the query performance. The ratio of index size to table size can vary greatly, depending on the columns, data types, and number of indexes on a table. Indexes and Data Modification Another downside to using an index is the performance implication on data modification statements. An index is associated with tables or table cluster that can speed data access and reducing disk I/O. By creating an index, You can retrieve related set of rows from table instead of All Rows. In database technologies (Oracle, SQL Server, Sybase, DB2, MySQL, PostreSQL, etc.), One index on a table is not a big deal. You automatically have an index on columns (or combinations of columns) that are primary keys or declared as unique. There is some overhead to an index. The index itself occupies space on disk and memory (when used). So, if space or memory are issues then too many indexes could be a problem.

5 May 2017 Reorganize has some advantages and disadvantages, due to the way it works… and it works completely different compared to the index 

In that case SQL Server will choose in the execution plan a Clustered Index Seek operator. Seek operations are very, very efficient, because SQL Server uses a B-tree structure to find the relevant data. A Non-Clustered Index you will use alongside a clustered index to improve read performance. You should put these on columns used in WHERE Clause, JOIN, etc and can include other columns that the query needs, to enhance performance even more. This is called a "covering index". So, in a nutshell, it is not the case of one being better than the other.

23 Mar 2016 Using SQL Server cursors – Advantages and disadvantages are only for demo purposes, and I made no index tuning to speed things up.

A Non-Clustered Index you will use alongside a clustered index to improve read performance. You should put these on columns used in WHERE Clause, JOIN, etc and can include other columns that the query needs, to enhance performance even more. This is called a "covering index". So, in a nutshell, it is not the case of one being better than the other. SQL is used as their standard database language by all the relational database management systems like Oracle, Informix, Posgres, SQL server, MySQL, MS Access, and Sybase. Also See: Characteristics of Database Approach. What is SQL, its Applications, Advantages and Disadvantages? History about SQL. In the 1970s, SQL was developed by the Raymond FF. An index is associated with tables or table cluster that can speed data access and reducing disk I/O. By creating an index, You can retrieve related set of rows from table instead of All Rows. In database technologies (Oracle, SQL Server, Sybase, DB2, MySQL, PostreSQL, etc.),

The cost of an index in disk space is generally trivial. The cost of additional writes to update the index when the table changes is often moderate. The cost in additional locking can be severe. It depends on the read vs write ratio on the table, and on how often the index is actually used to speed up a query.