Table of Contents
What is a synonym in a database?
In databases, a synonym is an alias or alternate name for a table, view, sequence, or other schema object. They are used mainly to make it easy for users to access database objects owned by other users.
How to check synonyms in Oracle Database?
- all_synonyms: View synonyms available to the current user.
- dba_synonyms: View all synonyms in the database.
- user_synonyms: Private synonyms owned by the current user.
What is database name in Oracle?
In Oracle RAC environments, the database name (DB_UNIQUE_NAME) portion is a string of no more than 30 characters that can contain alphanumeric, underscore (_), dollar ($), and pound (#) characters, but must begin with an alphabetic character. No other special characters are permitted in a database name.
How to create a synonym in Oracle?
To create a private synonym in another user’s schema, you must have the CREATE ANY SYNONYM system privilege. To create a PUBLIC synonym, you must have the CREATE PUBLIC SYNONYM system privilege. Specify OR REPLACE to re-create the synonym if it already exists.
How to use synonyms in SQL?
- In Object Explorer, expand the database where you want to create your new view.
- Right-click the Synonyms folder, then select New Synonym….
- In the Add Synonym dialog box, enter the following information. Synonym name. Type the new name you will use for this object. Synonym schema.
What are the types of synonyms in SQL?
| Synonym | SQL Server system data type |
|---|---|
| character | char |
| character | char(1) |
| character(n) | char(n) |
| character varying(n) | varchar(n) |
When to use synonyms in Oracle?
Oracle uses a public synonym only when resolving references to an object if the object is not prefaced by a schema and the object is not followed by a database link. If you omit this clause, the synonym is private and is accessible only within its schema. A private synonym name must be unique in its schema.
What is schema in Oracle?
A schema is a collection of database objects. A schema is owned by a database user and has the same name as that user. Schema objects are logical structures created by users. Objects such as tables or indexes hold data, or can consist of a definition only, such as a view or synonym.
How to drop a synonym in Oracle?
The syntax for the DROP SYNONYM command is: DROP SYNONYM synonym_name; If you drop or rename a table, view, or function that has an associated synonym, the synonym becomes an orphan. To reuse the synonym for another object with a different name, drop and re-create it.
What are the 5 database names?
MySQL, Oracle, PostgreSQL, Microsoft SQL Server, MongoDB, Redis, Elasticsearch, Cassandra, MariaDB, IBM Db2.
What is Oracle Database type?
Oracle Database uses the Oracle FLOAT data type internally when converting ANSI FLOAT data. Oracle FLOAT is available for you to use, but Oracle recommends that you use the BINARY_FLOAT and BINARY_DOUBLE data types instead, as they are more robust. Refer to Floating-Point Numbers for more information.
How to find all databases in Oracle?
Show Databases in Oracle If you want to see all of the pluggable databases (PDBs) on the server, you can run this: SELECT * FROM dba_pdbs; If you want to see a list of users or schemas on the server, you could query the dba_users view.
What is a synonym and homonym in database?
Also, in table “PROFESSOR”, there exists an attribute with name “student_number”. Then both the attributes are named as “Homonyms”. Synonyms: When more than one name is assigned to same attribute, the attribute names are referred as “synonyms’. It exists when the same attribute has more than one name.
What is the synonym of record in database?
Another name for a database record is a tuple. A set of records can be referred to as a data set, a data file, and a table.
What is use of synonym in Oracle?
A synonym is an alias for a schema object. You can create, view and drop a synonym. Synonyms can provide a level of security by masking the name and owner of an object and by providing location transparency for remote objects of a distributed database.
What are synonyms in SQL DBA?
In SQL Server, the synonym is the database object that provides alternate name (alias) to another database objects such as table, view, stored procedure, etc. in the local server or a remote server.