Rename column

Ushbu qo'llanmada siz jadvalning bir yoki bir nechta ustunlari nomini o'zgartirish uchun ALTER TABLE iborasidagi PostgreSQL RENAME COLUMN bandidan qanday foydalanishni o'rganasiz.

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Jadval ustunining nomini o'zgartirish uchun siz ALTER TABLE iborasidagi RENAME COLUMN bandidan quyidagi tarzda foydalanasiz:

ALTER TABLE table_name 
RENAME COLUMN column_name TO new_column_name;

Ushbu bayonotda:

• Birinchidan, ALTER TABLE bandidan keyin nomini o'zgartirmoqchi bo'lgan ustunni o'z ichiga olgan jadval nomini belgilang.

• Ikkinchidan, RENAME COLUMN kalit so'zlaridan keyin nomini o'zgartirmoqchi bo'lgan ustun nomini ko'rsating.

• Uchinchidan, TO kalit so'zidan keyin ustun uchun yangi nomni belgilang.

Bayonotdagi COLUMN kalit so'zi ixtiyoriy, shuning uchun uni quyidagi tarzda o'tkazib yuborishingiz mumkin:

ALTER TABLE table_name 
RENAME column_name TO new_column_name;

Ba'zi sabablarga ko'ra, mavjud bo'lmagan ustun nomini o'zgartirmoqchi bo'lsangiz, PostgreSQL xatolik chiqaradi. Afsuski, PostgreSQL RENAME bandi uchun IF EXISTS opsiyani taqdim etmaydi.

Bir nechta ustunlar nomini o'zgartirish uchun siz RENAME buyrug'ini bir vaqtning o'zida bir ustunni bir necha marta bajarishingiz kerak:

ALTER TABLE table_name
RENAME column_name1 TO new_column_name1;

ALTER TABLE table_name
RENAME column_name2 TO new_column_name2;

view, foreign key cheklovlari, triggerlar va stored prosedura kabi boshqa maʼlumotlar bazasi obyektlari tomonidan havola qilingan ustun nomini oʻzgartirsangiz, PostgreSQL bogʻliq obʼyektlardagi ustun nomini avtomatik ravishda oʻzgartiradi.

Keling, yaxshiroq tushunish uchun ALTER TABLE RENAME COLUMN dan foydalanishga misollar keltiraylik.

Namuna jadvallarini o'rnatish

Birinchidan, ikkita yangi customers va customer_groups jadvalirini yarating.

CREATE TABLE customer_groups (
    id serial PRIMARY KEY,
    name VARCHAR NOT NULL
);

CREATE TABLE customers (
    id serial PRIMARY KEY,
    name VARCHAR NOT NULL,
    phone VARCHAR NOT NULL,
    email VARCHAR,
    group_id INT,
    FOREIGN KEY (group_id) REFERENCES customer_groups (id)
);

Keyin, customers va customers_group jadvallari asosida customer_data nomli yangi ko'rinish yarating.

CREATE VIEW customer_data 
AS SELECT
    c.id,
    c.name,
    g.name customer_group
FROM
    customers c
INNER JOIN customer_groups g ON g.id = c.group_id;

Bitta ustun nomini oʻzgartirish uchun RENAME COLUMNE dan foydalanish

Quyidagi bayonot customers jadvalining email ustunini contact_email ga o'zgartirish uchun ALTER TABLE RENAME COLUMN bayonotidan foydalanadi:

ALTER TABLE customers 
RENAME COLUMN email TO contact_email;

Bog'liq ob'ektlarga ega bo'lgan ustun nomini o'zgartirish uchun RENAME COLUMN dan foydalaning

Ushbu misolda customers jadvalining name ustunini group_name ga o'zgartirish uchun ALTER TABLE RENAME COLUMN iborasidan foydalaniladi. name ustuni customer_data ko'rinishida ishlatiladi.

ALTER TABLE customer_groups 
RENAME COLUMN name TO group_name;

Endi siz name ustunining o'zgarishi customer_data ko'rinishiga kaskadlanganligini tekshirishingiz mumkin:

test=# \d+ customer_data;
                       View "public.customer_data"
     Column     |       Type        | Modifiers | Storage  | Description
----------------+-------------------+-----------+----------+-------------
 id             | integer           |           | plain    |
 name           | character varying |           | extended |
 customer_group | character varying |           | extended |
View definition:
 SELECT c.id,
    c.name,
    g.group_name AS customer_group
   FROM customers c
     JOIN customer_groups g ON g.id = c.group_id;

Ko'rinish ta'rifida ko'rib turganingizdek, name ustuni group_name ga o'zgartirildi.

Bir nechta ustun nomini oʻzgartirish uchun bir nechta RENAME COLUMNdan foydalanish misoli

Ushbu bayonotlar customers jadvalining ikkita ustun name va phone mos ravishda customer_name va contact_phonega o'zgartiradi:

ALTER TABLE customers 
RENAME COLUMN name TO customer_name;

ALTER TABLE customers
RENAME COLUMN phone TO contact_phone;

Ushbu qo'llanmada siz ustun nomini o'zgartirish uchun ALTER TABLE iborasidagi PostgreSQL RENAME COLUMN bandidan qanday foydalanishni o'rgandingiz.

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