Oracle priekšraksts ALTER TABLE norāda, kā pievienot, modificēt, nomest vai dzēst tabulas kolonnas. To izmanto arī, lai pārdēvētu tabulu.

Kā tabulai pievienot kolonnu

Sintakse:

 ALTER TABLE table_name ADD column_name column-definition; 

Piemērs:

python konstruktors

Apsveriet, ka jau esošie galda klienti. Tagad pievienojiet jaunu kolonnu klienta_vecums tabulai Klienti.

 ALTER TABLE customers ADD customer_age varchar2(50); 

Tagad klientu tabulā tiks pievienota jauna kolonna “customer_age”.

Kā esošajai tabulai pievienot vairākas kolonnas

Sintakse:

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

Piemērs

 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. 

Kā mainīt tabulas kolonnu

Sintakse:

 ALTER TABLE table_name MODIFY column_name column_type; 

Piemērs:

prioritārā rinda

 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. 

Kā mainīt vairākas tabulas kolonnas

Sintakse:

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

Piemērs:

 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. 

Kā nomest tabulas kolonnu

Sintakse:

 ALTER TABLE table_name DROP COLUMN column_name; 

Piemērs:

 ALTER TABLE customers DROP COLUMN customer_name; 

 This will drop the customer_name column from the table. 

Kā pārdēvēt tabulas kolonnu

Sintakse:

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 ALTER TABLE table_name RENAME COLUMN old_name to new_name; 

Piemērs:

 ALTER TABLE customers RENAME COLUMN customer_name to cname; 

 This will rename the column customer_name into cname. 

Kā pārdēvēt tabulu

Sintakse:

 ALTER TABLE table_name RENAME TO new_table_name; 

Piemērs:

 ALTER TABLE customers RENAME TO retailers; 

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