sql managment

1, please simply explain the advantages and disadvantages of database indexingUsing an index can speed up the query of your data, but because it is indexed during data insertion, it slows the insertion and update of data, and the index takes up disk

1, please simply explain the advantages and disadvantages of database indexingUsing an index can speed up the query of your data, but because it is indexed during data insertion, it slows the insertion and update of data, and the index takes up disk

What is the use of 2.1.using keywords? What is IDisposable?The using can declare the introduction of namespace, and can also implement the release of unmanaged resources, implement the Idisposiable class in the using, and automatically invoke the

1, please simply explain the advantages and disadvantages of database indexingUsing an index can speed up the query of your data, but because it is indexed during data insertion, it slows the insertion and update of data, and the index takes up disk

There are five types of constraints in SQL Server, namely the PRIMARY key constraint, the FOREIGN key constraint, the unique constraint, the default constraint, and the check constraint. View or create constraints that you want to use to Microsoft

Constraint definitionsFor a database, the integrity constraints of the basic table are divided into column-level constraints and table-level constraints:Column-level constraint conditionsA column-level constraint is a constraint on a particular

The http://blog.csdn.net/zhangking/article/details/5670070 MySQL cluster is a highly available, highly redundant version of MySQL suitable for distributed computing environments. It employs the NDB Cluster storage engine, which allows multiple MySQL

?. Oracle EBS (ERP)Oracle is the company name, which I guess everyone knows.EBS is the acronym for E-business Suite, simply speaking, Oracle does an enterprise-class information software or system, which contains the financial, human, distribution,

MySQL clustering is a technology that allows you to deploy the Cluster of the in-memory and disk databases on systems that are not shared. With no shared architecture, the system can use inexpensive hardware and no special requirements for hardware

MySQL clustering is a highly available, highly redundant version of MySQL for distributed computing environments. It employs a NDB Cluster storage engine that allows multiple MySQL servers to be run in 1 clusters. The storage engine is available in