sql server sparse columns performance

; +----+-------------+-------+-------+---------------+---------+---------+------+------+-------+ | id | select_ Type | Table | Type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+---------------+---------+---------+------+------+-------+ | 1 | Simple | film | index | NULL | PRIMARY | 2 | NULL | 55 | NULL | +----+-------------+-------+-------+---------------+---------+---------+------+------+-------+ 1 row in Set ( 0.00 se

1. The question The system has a module that needs to query the data in the Oracle database. It is now implemented by establishing a linked server. SQL Server access Oracle implementation can refer to this article http://www.cnblogs.com/gnielee/archive/2010/09/07/access-oracle-from-sqlserver.html The current query statement is a simple query with a where condi

Label:Sometimes, in order for the application to run faster, all that is done is to make minor adjustments here or there. But the key is to determine how to adjust! Sooner or later you'll encounter this scenario: the SQL query in your application doesn't respond the way you want. It either doesn't return data, or it takes a surprisingly long time. If it lowers the speed of the enterprise application, the user must wait a long time. Users expect applic

database design and access to its query. In this month's column, I will talk about four technologies that can be used to improve the performance of SQL Server? Or improve the scalability of the application. I will carefully describe the use of left join and cross join and the retrieval of identity values. Remember, there is no magic solution at all. Adjusting yo

When we want to count the total number of records in a datasheet, we use the T-SQL function count (*). If this function is executed in a large table containing millions of rows, it can take a long time to return the total number of records in the entire table, which results in a decrease in query performance. First, the general approach: using the count () function Each database administrator knows how to

] ')This allows you to see the foreign keys in the SalesOrder table (if any)But if so, I do not have to query every table, Google to find a solution, with a SQL statement to do all, as follows:--using Sysreferences--Delete foreign keyDECLARE @SQL VARCHAR( -)DECLARECur_fkCURSORLOCAL forSELECT 'ALTER TABLE ['+ object_name(Fkeyid)+ '] Drop constraint' + object_name(ConstID) fromsysreferences--Delete all foreig

. In this month's column, I will talk about four technologies that can be used to improve the performance of SQL Server? Or improve the scalability of the application. I will carefully describe the use of left join and cross join and the retrieval of identity values. Remember, there is no magic solution at all. Adjusting your database and its query takes time and

Tags: instance default help input extern data package MSDN One fixOriginal: SQL Server performance Tuning resource waiting network I/OI. OverviewThe main wait for network I/O is async_network_io, when SQL Server returns a data result set to the client, the result set is popu

Permission management is involved in program development. The system uses an integer to record user permissions. The permission level is set: Level1 1 Level2 2 Level3 4 Level4 8 Level5 16 Level6 31 Level7 32 Level8 64 Level9 127 Level10 128 Level11 255 Level12 65535 In the database, if a user A has a permission level of 1, his three

)Untyped XML is not expressed in XML schema. It is saved as a Unicode string in SQL Server. Storage. For their operations, data needs to be converted to the corresponding type. For example (/book/price) [1]> 19.99, Decimal process. A large number of similar comparisons consume a lot of resources, which leads to the importance of type information in XML schema.Type information works in the following aspects

system into multiple nodes, each node's processor can only access its own local resources, is a completely unshared architecture. Data exchange between nodes requires software implementation. Its advantage is that scalability is very good, the disadvantage is that data exchange difficulties with each other, the need to control a lot of software work to achieve communication and task allocation, scheduling, for the general enterprise applications is too complex, inefficient. NUMA (non-uniform

Many enterprises also use various versions of Windows 9x in various contexts, so in order to use SQL Server 2000 in these environments, we must first understand the performance and limitations of Windows 9x. Client software SQL Server 2000 client software is included with

; } /// ///User Account/// Public stringUserName {Set;Get; } /// ///User Password/// Public stringPassWord {Set;Get; } /// ///Nickname/// Public stringNickname {Get;Set; } /// ///Encrypted Salt/// Public stringSalt {Set;Get; } /// ///whether to freeze/// Public BOOLIsFrozen {Set;Get; } /// ///Balance/// Public decimalBalance {Set;Get; } /// ///Department/// Public stringDepartme

large table to be used frequently, build a clustered index. The data column where the index is located should be one or several repeating records that are not many columns of data.Some other databases in the industry may not emphasize the concept of clustered indexes or use other methods to manage tables. So if you put a non-SQLServer's database is migrated to SQL Serv