U Oracleu, izjava ALTER TABLE navodi kako dodati, izmijeniti, ispustiti ili izbrisati stupce u tablici. Također se koristi za preimenovanje tablice.

Kako dodati stupac u tablicu

Sintaksa:

 ALTER TABLE table_name ADD column_name column-definition; 

Primjer:

java povezivost

Uzmite u obzir da već postojeća tablica kupaca. Sada dodajte novi stupac customer_age u tablicu kupaca.

 ALTER TABLE customers ADD customer_age varchar2(50); 

Sada će se novi stupac 'customer_age' dodati u tablicu kupaca.

Kako dodati više stupaca u postojeću tablicu

Sintaksa:

 ALTER TABLE table_name ADD (column_1 column-definition, column_2 column-definition, ... column_n column_definition); 

Primjer

 ALTER TABLE customers ADD (customer_type varchar2(50), customer_address varchar2(50)); 

 Now, two columns customer_type and customer_address will be added in the table customers. 

Kako modificirati stupac tablice

Sintaksa:

 ALTER TABLE table_name MODIFY column_name column_type; 

Primjer:

odabir više tablica sql

 ALTER TABLE customers MODIFY customer_name varchar2(100) not null; 

 Now the column column_name in the customers table is modified to varchar2 (100) and forced the column to not allow null values. 

Kako izmijeniti više stupaca u tablici

Sintaksa:

 ALTER TABLE table_name MODIFY (column_1 column_type, column_2 column_type, ... column_n column_type); 

Primjer:

 ALTER TABLE customers MODIFY (customer_name varchar2(100) not null, city varchar2(100)); 

 This will modify both the customer_name and city columns in the table. 

Kako ispustiti stupac tablice

Sintaksa:

 ALTER TABLE table_name DROP COLUMN column_name; 

Primjer:

 ALTER TABLE customers DROP COLUMN customer_name; 

 This will drop the customer_name column from the table. 

Kako preimenovati stupac tablice

Sintaksa:

konačni stroj

 ALTER TABLE table_name RENAME COLUMN old_name to new_name; 

Primjer:

 ALTER TABLE customers RENAME COLUMN customer_name to cname; 

 This will rename the column customer_name into cname. 

Kako preimenovati tablicu

Sintaksa:

 ALTER TABLE table_name RENAME TO new_table_name; 

Primjer:

 ALTER TABLE customers RENAME TO retailers; 

 This will rename the customer table into 'retailers' table.