How do I find db links in my database?
Any user can query USER_DB_LINKS to determine which database links are available to that user. Only those with additional privileges can use the ALL_DB_LINKS or DBA_DB_LINKS view.
Does Oracle have a data dictionary?
The data dictionary has three primary uses: Oracle accesses the data dictionary to find information about users, schema objects, and storage structures. Oracle modifies the data dictionary every time that a data definition language (DDL) statement is issued.
How does DB Link work in Oracle?
When the database link in the preceding query is used, Oracle will log into the database specified by the database link, using the username and password provided by the link. It then queries the BOOKSHELF table in that account and returns the data to the user who initiated the query.
How can I see all db links in Oracle?
These views are helpful for working with DB links in Oracle:
- DBA_DB_LINKS – All DB links defined in the database.
- ALL_DB_LINKS – All DB links the current user has access to.
- USER_DB_LINKS – All DB links owned by current user.
What are db links?
A database link is a connection between two physical database servers that allows a client to access them as one logical database.
What is data dictionary in Oracle example?
The Oracle data dictionary is metadata about the database. For example, if you create a table in Oracle, metadata about that table is stored in the data dictionary. Such things as column names, length, and other attributes are stored.
What is data dictionary table in Oracle?
A data dictionary contains: The definitions of all schema objects in the database (tables, views, indexes, clusters, synonyms, sequences, procedures, functions, packages, triggers, and so on) How much space has been allocated for, and is currently used by, the schema objects. Default values for columns.
How do I query a table using a db link?
In SQL statements, you can refer to a table or view on the other database by appending @dblink to the table or view name. You can query a table or view on the other database with the SELECT statement. You can also access remote tables and views using any INSERT , UPDATE , DELETE , or LOCK TABLE statement.
Which is used to link to the database?
Use the CREATE DATABASE LINK statement to create a database link. A database link is a schema object in one database that enables you to access objects on another database. The other database need not be an Oracle Database system. However, to access non-Oracle systems you must use Oracle Heterogeneous Services.
What is db links?
How is db link created?
To create a private database link, you must have the CREATE DATABASE LINK system privilege. To create a public database link, you must have the CREATE PUBLIC DATABASE LINK system privilege. Also, you must have the CREATE SESSION system privilege on the remote Oracle database.