DDL, DML, DCL da TCL menene?

Question

Accepted Answer

Umarnin SQL an raba su zuwa **nau'i** bisa ga niyarsu: **DDL** (ayyana tsarin bayanai), **DML** (canja yadda ake aiki da bayanai), **DCL** (sarrafa tufarewa), da **TCL** (sarrafa jujjuyawa). Fahimtar waɗannan nau'ikan zai shirya iliminka na SQL kuma zai bayyana yadda ake tsara harshen.

## DDL — Data Definition Language (yana ayyana tsari)

```sql
CREATE TABLE users (id INT, name VARCHAR(100));   -- create a table/index/database
ALTER TABLE users ADD COLUMN email VARCHAR(255);   -- modify structure
DROP TABLE users;                                   -- delete a table
TRUNCATE TABLE logs;                                -- empty a table (fast)
```

DDL yana ayyana da canja tsarin banki na bayanai **schema** (tables, columns, indexes, constraints). Lura: Umarnin DDL yawanci **suka ba da izini ta atomatik** (ba za a iya soba su cikin jujjuyawa a yawancin bankin bayanai ba).

## DML — Data Manipulation Language (canja bayanai)

```sql
SELECT * FROM users;                  -- read (sometimes classed as DQL)
INSERT INTO users VALUES (...);        -- add rows
UPDATE users SET name = 'X' WHERE ..;  -- modify rows
DELETE FROM users WHERE ...;            -- remove rows
```

DML yana aiki da **bayanai a cikin** tables — jiyan neman bayanai da canja. (`SELECT` wani lokaci ana rabu da shi azaman DQL, Data Query Language.)

## DCL — Data Control Language (izini)

```sql
GRANT SELECT, INSERT ON users TO analyst;   -- give permissions
REVOKE INSERT ON users FROM analyst;         -- take them away
```

DCL yana sarrafa **sarrafa tufarewa** — ba da izini da soke izini akan abubuwan banki na bayanai (tsaron gida).

## TCL — Transaction Control Language

```sql
BEGIN;                       -- start a transaction
COMMIT;                       -- save all changes permanently
ROLLBACK;                     -- undo changes since the last commit
SAVEPOINT sp1;                -- a partial rollback point
ROLLBACK TO sp1;
```

TCL yana sarrafa **jujjuyawa** — ba da bada izini, soba, da savepoints (garantin duka ko babu da babu).

## Taƙaitawa

```text
DDL → CREATE, ALTER, DROP, TRUNCATE   — define/modify SCHEMA (structure)
DML → SELECT, INSERT, UPDATE, DELETE  — work with DATA
DCL → GRANT, REVOKE                    — control ACCESS (permissions)
TCL → COMMIT, ROLLBACK, SAVEPOINT      — control TRANSACTIONS
```

## Menene mahimmancin hakan

Fahimtar nau'i na DDL/DML/DCL/TCL shine ilimi mai daraja wanda **zai shirya fahimtarka na SQL** — yana ba da kyakkyawar tsanin aiki ga nau'i daban-daban na aiki waɗanda SQL ke aiki, wanda ke taimakon ilimta, bada labari game da, da yin tunani game da umarnin banki na bayanai.

Sanin nau'in zai bayyana niyoyi daban-daban: **DDL** (ayyana da canja tsari — tables, indexes, constraints), **DML** (ayyukan bayanai na yau-yau — neman bayanai da canja layuka), **DCL** (sarrafa tufarewa — izini don tsaron gida), da **TCL** (sarrafa jujjuyawa — ba da bada izini/soba wanda ke ba da garantin ingantarwa na bayanai).

Waɗannan nau'in yana da maiyar fa'ida ga wasu dalilai: yana taimakon fahimta tsarin SQL a matsayin cikakken harshe (ba kawai umarnin waɓe waɓe ba), yana bayyana bambance-bambancen muhimman hali (misali **DDL yawanci yana ba da izini ta atomatik** kuma ba za a iya soba ta haka ba, ba kamar DML ba wanda zai aiki a cikin jujjuyawa — bambance-bambance mai mahimmanci a aiki), kuma yana ba da kamus na sadarwa don magana game da ayyukan banki na bayanai.

Fahimtar cewa ayyana tsari (DDL), canja bayanai (DML), sarrafa tufarewa (DCL), da sarrafa jujjuyawa (TCL) nau'i daban-daban ne tare da bambance-bambancen hali da niyoyi yana ba ka tsanin aiki don cikakken jiya na SQL.

A yaji cewa wannan ya fi kusan tunani fiye da wata wata technique, fahimtar nau'in umarnin SQL yana da daraja a matsayin ilimi na asali wanda zai shirya fahimtarka na gabaɗaya na SQL, yana bayyana bambance-bambancen hali (kamar DDL auto-commit), kuma shine jiya da aka sani a hankali wanda ke nuna tsanin tsari na harshen SQL da nau'i-nau'ina daban-daban na aiki — tunani mai amfani a shirya ilimika cikakke na SQL.