Guidelines for estimating the space needed for a database
Explain some guidelines for estimating the space needed for a database.Guidelines for estimating spaces needed for a database:
 For every table in the database, find an average size that every row would need.  Estimate the size of indexes for every table based on type and number of indexes. This should include both clustered and unclustered indexes.  Consider fill facto and pad index used while creating indexes.  Find how many rows can fit into a single 8Kb page.  Estimate the size of the heap.Explain some guidelines for estimating the space needed for a database.Estimating the space needed for a database is essential to figure out the performance of the application and size of database. Following guidelines could help estimating the space:
 The size of each table in the database should be estimated by calculating the space required for indexes and heaps.  The size of a clustered index can be calculated by calculating the space used to store data in the leaf level of the clustered index and the space used to store index information for the clustered index.  The size of a non clustered index can be calculated by calculating the space used to store data in the leaf level of the non clustered index and the space used to store index information for non leaf of the non clustered index. Explain some guidelines for estimating the space needed for a database.Here are some guidelines for estimating the space needed for a database.
 The size of the tables can be found out by calculating the bytes the rows occupy. For that tables which do not have a fixed size, their column sizes can be determined by taking the average from the actual data.  Then the type and number of indexes that will be used for each table need to be estimated. (clustered or nonclustered, the number of indexes, and the width of the indexes).  The Fillfactor and Pad Index used when the indexes are created also need to be considered. The empty space that these factors affect need to be taken into consideration.  The amount of space taken to store data in a table depends on the number of rows that can be fit in an 8K SQL Server data page. This could account for the unused space of the page size in the estimation.

What is IN operator?IN operator in a query allows you to have multiple values in a WHERE clause.........