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What else can I help you with?
What is difference between alter and modify on oracle?
MODIFY is a clause used within an ALTER statement, such as ALTER TABLE, ALTER INDEX or ALTER MATERIALIZED VIEW, etc. That is, MODIFY isn't a command by itself. For example, you might change the length of a text column in a table with the following: ALTER TABLE employee MODIFY (email_address VARCHAR(132));
What is all about oracle 10g and oracle8i?
The oracle 10g and oracle 8i there is a minor difference that is oracle 8i doesn't support flash back command once we drop the table in database the message is table dropped but we can use flashback command we can retrieve the drop table once in database
How do you create a primay key in Oracle?
You can create a primary key column in an oracle table using the PRIMARY KEY keyword. Assuming you have an employee table that has employee information and has a column called emp_num. you can create a primary key in the table using the below command. ALTER TABLE tbl_employee_info add CONSTRAINT emp_pk PRIMARY KEY (emp_num) If you execute the above command in your database, emp_num will become the primary key of the table tbl_employee_info.
What is an alter table?
Alter table command is not a part of the ANSI standard, but is widely available. Its form is fairly consistent, although its capabilities vary considerably.
How do you alter foreign keys in oracle?
To alter foreign keys in Oracle, you can use the ALTER TABLE statement. To modify an existing foreign key constraint, you typically need to drop the existing constraint first using ALTER TABLE table_name DROP CONSTRAINT constraint_name, then add a new foreign key constraint with the desired modifications using ALTER TABLE table_name ADD CONSTRAINT constraint_name FOREIGN KEY (column_name) REFERENCES other_table (other_column). If you only need to disable or enable the constraint without altering it, you can use ALTER TABLE table_name DISABLE CONSTRAINT constraint_name or ENABLE CONSTRAINT.
Oracle Alter a column's varchar length I want to change a varchar30 to a varchar20. can please help me get the syntax for it?
ALTER TABLE table_name MODIFY (column_name VARCHAR2(20));
How do you disable constraints in dbms?
To disable constraints in a DBMS, you typically use specific SQL commands tailored to the database system in use. For example, in Oracle, you can use the command ALTER TABLE table_name DISABLE CONSTRAINT constraint_name;. In SQL Server, you would use ALTER TABLE table_name NOCHECK CONSTRAINT constraint_name;. Always remember to re-enable the constraints after your operations to maintain data integrity.
Query used to add fields to existing tables?
The query can be called an Append query. New columns can be added to existing tables by using the ALTER TABLE command in SQL. ex: ALTER TABLE tbl_employee ADD emp_address VARCHAR(100); The above command adds a column emp_address to an existing table tbl_employee
Can you add new columns to a database after creating the structure?
Columns are added to a table, not a database (which is a collection of tables). Adding a column to a table is achieved by using the Alter Table SQL command.
How do you restore a table deleted from oracle 10g?
If you are on 10g or later and the recycle bin feature is turned on, you can use the FLASHBACK TABLE x TO BEFORE DROP command, where x is the name of the table. If it is not there, or the recycle bin feature is not available, you will have to restore the table from a backup.
What is space table in oracle?
Oracle table space is an identifier for a physical file found at the operating system level.
What is default table space in oracle?
DUAL table
