Constraints are rules you can define in your Oracle tables to restrict the type of data you can place in the tables. Two methods exist for defining constraints: the table constraint method and the column constraint method. The constraint is defined as a table constraint if the constraint clause syntax appears after the column […]
Global temporary tablesGlobal temporary tables are distinct within SQL sessions.The basic syntax is: CREATE GLOBAL TEMPORARY TABLE table_name ( …);For example: CREATE GLOBAL TEMPORARY TABLE supplier ( supplier_id numeric(10) not null, supplier_name varchar2(50) not null, contact_name varchar2(50) ) This would create a […]
Views are queries stored in Oracle that dynamically assemble data into a virtual table. To the person using the view, manipulating the data from the view is just like manipulating the data from a table. In some cases, it is even possible for the user to change data in a view as though the view […]
The DROP TABLE statement allows you to remove a table from the database.The basic syntax for the DROP TABLE statement is: DROP TABLE table_name;For example: DROP TABLE XX_supplier;This would drop table called XX_supplier.Sometimes objects are associated with a table that exists in a database along with the table. These objects may include indexes, constraints, and […]
The ALTER TABLE statement allows you to rename an existing table. It can also be used to add, modify, or drop a column from an existing table.Renaming a tableThe basic syntax for renaming a table is: ALTER TABLE table_name RENAME TO new_table_name;For example: ALTER TABLE suppliers RENAME TO vendors;This will rename the suppliers table to […]
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