.NET/Java PDF, Tiff, Barcode SDK Library

Every Oracle database contains a set of read-only tables, which contain metadata (information about the various component of the database). The Oracle data dictionary is the heart of the database management system, and mastery of it will take you far in your quest to become an expert DBA. If you understand the data dictionary well, you can easily perform database management tasks. The data dictionary tables are located in the System tablespace and are read-only for all the database users except the user SYS. The data dictionary tables are updated when any database objects or user information changes (any DDL changes in the database modify the data dictionary). Following are some of the key database items for which you can use the data dictionary: User information Object information (tables, indexes, packages, and so on) Roles and privileges Constraint information Storage information (data files and tablespaces) Auditing information Operational information (backups, log files, archive log files, and so on)

barcode font in excel 2010, how to add barcode font to excel 2003, 2d barcode excel 2013, create barcode labels in excel 2010, how to add barcode font in excel 2010, free barcode font excel 2007, barcode for excel 2007 free, free3of9 barcode font excel, how to use barcode font in excel 2010, barcode generator excel freeware,

Oracle doesn t allow you to access the internal data dictionary tables directly. It creates views on the base dictionary tables and creates public synonyms for these views so users can access them. There are three sets of data dictionary views USER, ALL, and DBA with each set of views pertaining to a similar item containing similar columns. The views in each category are prefixed by the keywords USER, ALL, or DBA. Each of these sets of views shows only the information the user is granted privileges to access, as follows: USER: The USER views show a user only those objects that the user owns. These views are useful to users, especially developers, for viewing the owner s objects, grants, and so on. ALL: The ALL views show you information about objects for which you have been granted privileges. The views with the prefix ALL include information on the user s objects, and all other objects on which privileges have been granted, directly or through a role. DBA: The DBA views are the most powerful in their range. Users who have been assigned the DBA role can access information about any object or any user in the database. The DBAprefixed dictionary views are the ones you use to monitor and administer the database.

The data dictionary is created automatically when you create the database. Well, almost automatically, because you do have to run the catalog.sql script manually (located in the $ORACLE_HOME/ rdbms/admin directory) if you aren t using the Database Configuration Assistant. The catalog.sql script creates the data dictionary tables, views, and synonyms, and they re the first set of objects to populate the database. The data dictionary, once created, has to remain in the System tablespace. In the rest of the chapter, you ll see detailed references to the DBA data dictionary tables only, because your focus is database management. There are many data dictionary tables and views. You ll examine the most useful of the data dictionary views in the next few sections.

// if successful ... try { // ... assign tracking handle of new object to member variable this->sr = sr; // call base class constructor Object::Object(); // code for the constructor's body goes here } // if base class constructor has failed catch (Object^ o) { // ... "undo" initialization of second sub-object delete sr; // ... rethrow for further undoings throw; } } // if base class constructor or initialization of second sub-object failed ... catch (Object^ o) { // ... "undo" initialiization of first sub-object delete fs; // rethrow exception to the code that tried to instantiate FileDumper throw; } } The code shown here ensures that in case of an exception thrown during object construction, all sub-objects created so far will be deleted. This behavior is analogous to the C++ construction model. The following pseudocode shows the implementation of the destruction logic: public ref class FileDumper : IDisposable { public: virtual void Dispose() { Dispose(true); // pseudocode