MonetDB用户指南3——Readonly database只读数据库

来源：http://www.monetdb.org/Documentation/readonly-database

 

When working in a regular mode, the query processing spans the basic column storage and the data changed by transactions (inserts, updates, and deletes). For instance, the inserted data, kept in a separate delta structure, are added to the column before other operations in the plan. In a 'read-only mode' modifying transactions are not allowed and the query processing spans only over the basic column storage. One of the consequences is that query execution may become faster.

The readonly mode is administered with a boolean variable, which  can be set by the system administrator using themonetdb tool:

shell> monetdb set readonly=yes <mydatabasename>

It ensures that all tables are accessed in read only mode.  Moreover, the database is protected against any catalog change, the user can not even create a temporary table for keeping an intermediate result around.

The alternative route is to deploy SQL schemas in combination with user authentication and access control grants to selectively allow users access to the database. See the corresponding description in theSQL manual.

 

 

在普通模式下工作时，查询处理事务跨越基本列存储和数据改变（插入，更新，删除）。例如，插入的数据，保存在一个单独的delta结构。在一个只读模式修改交易是不允许,查询处理的跨度仅在基本列存储。后果之一是，查询的执行可能会变得更快。

在只读模式是使用一个布尔变量，可以通过设置使用MonetDB工具系统管理员：

shell> monetdb set readonly=yes <mydatabasename>

 

shell> monetdb set readonly=yes <mydatabasename>

 

它确保所有的表都是以只读方式访问。此外，该数据库是防止任何（数据库元数据catalog）目录的变化，用户甚至不能用临时表保存中间结果。

的另一种途径是在与用户的身份认证和访问控制授权选择性地允许用户访问数据库结合SQL架构部署。看在SQL手册相应的描述。