updates the data dictionary continuously to reflect changes in database structures, auditing, grants, and data. The views of the data dictionary serve as a reference for all database users. Access the data dictionary views with SQL statements. Some views are accessible to all Oracle users, and others are intended for database administrators only. The data dictionary is always available when the database is open. It resides in the system tablespace, which is always online. The oracle data dictionary has three primary uses: 01)The oracle server uses it to find information about: Users Schema objects Storage structures 02)The Oracle server modifies it when a DDL statement is executed 03)Users and DBA can use it as a read-only reference for information about the database ANSWER 4: The data dictionary consists of three main sets of static views distinguished from each other by their scope: CATEGORIES SCOPES DBA What is in all the schema ALL What the user can access USER What is in the user’s schemaDBA: Views with the prefix DBA show a global view of the entire database. Synonyms are not created for these views, because DBA views should be queried only by administrators. ALL:
Views with the prefix ALL refer to the user's overall perspective of the database. These views return information about schema objects to which the user has access through public or explicit grants of privileges and roles, in addition to schema objects that the user owns. USER: Refer to the user's own private environment in the database, including information about schema objects created by the user, grants made by the user, and so on, Display only rows pertinent to the user and also Have columns identical to the other views, except that the column owner is implied that also Return a subset of the information in the ALL views and Can have abbreviated public synonyms for convenience ANSWER 5: The Oracle7 Server contains a set of underlying tables that are maintained by the Server and accessible to the DBA user SYS. These tables are called dynamic performance tables because they are continuously updated while a database is open and in use, and their contents relate primarily to performance. Dynamic performance tables are useful for identifying instance-level performanceproblems.