database schema for messaging system

same as the user name and serves as the user's default schema. This is why the schema names are database usernames in the Enterprise Manager Solution. You cannot create a new schema in an Oracle database. To create a schema, you

multiple external modes;② external mode is the user view;③ External mode is a powerful measure to ensure data security.Three, internal mode (Internal schema)Definition: Also known as the storage mode (Storage schema), it is a description of the physical structure and storage of the data, is the representation of the data within the database (for example, the sto

A dedicated administrator is established on the server database because the test wants to delete it, but always prompts the user to have the schema cannot be deleted, and the schema display db_owner can not be changed, I use the sqlserver2008. Deleting a database user in SQL Server2000 is simple, as long as you delete

As a result of the writing of an article also just contact Postfix, the e-mail system is also very superficial understanding, although barely built to run the mail system, but also exposed a lot of problems. At the same time blind pursuit of function, make the whole installation process is long, for want to get started friend is more difficult. This time I will revise the previous article, and remove the se

designs According to the SQL standard, both Catalog and Schema are abstract concepts in the SQL environment. they can be understood as a layer in a container or database object namespace, it is mainly used to solve naming conflicts. Conceptually, a database system contains multiple Catalog S, each of which contains mu

is not used to create a schema). When creating a user, create a schem with the same name as the user name and use it as the default shcema for the user. That is to say, the number of schemas is the same as the number of users, and the schema names are one-to-one and the same as the names of users. All aliases that can be called schema as users are inaccurate, bu

greater than the frequency of the update, in exchange for more performance gains through the cost of a small part of the operation, which is in fact the strategy used frequently in our system performance optimization.In most applications, such queries, similar to the one in the example above, are very large, but the data is much more frequent, and many times if we blindly pursue the paradigm-theoretic schema