SQL · Theory

DBMS

Theory

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DBMS

DBMS is the software that manages databases — MySQL Server is a DBMS. A database is the data (college). The DBMS stores it, locks it, backs it up, and runs SQL.

RDBMS is a DBMS that uses relational tables (rows/columns/keys). MySQL is an RDBMS. MongoDB is a DBMS that is document-based, not relational.

Trap: ‘MySQL is a database’ vs ‘MySQL is a DBMS’. Casual speech says both. Viva: DBMS = software, database = the stored data.

On the example next to this theory: DBMS: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Exam tip

MySQL Server = RDBMS. college = a database inside it.

DBMS — sample query

-- DBMS
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

DBMS: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

DefDBMS = software. Database = the data. MySQL is an RDBMS.
RuleRDBMS = tables + keys + SQL.
TrapMixing DBMS and ‘a database’ in a strict viva.

SQL · Theory

DBMS

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Theory

376/439

DBMS

DBMS is the software that manages databases — MySQL Server is a DBMS. A database is the data (college). The DBMS stores it, locks it, backs it up, and runs SQL.

RDBMS is a DBMS that uses relational tables (rows/columns/keys). MySQL is an RDBMS. MongoDB is a DBMS that is document-based, not relational.

Trap: ‘MySQL is a database’ vs ‘MySQL is a DBMS’. Casual speech says both. Viva: DBMS = software, database = the stored data.

On the example next to this theory: DBMS: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Exam tip

MySQL Server = RDBMS. college = a database inside it.

DBMS — sample query

-- DBMS
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

DBMS: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

DefDBMS = software. Database = the data. MySQL is an RDBMS.
RuleRDBMS = tables + keys + SQL.
TrapMixing DBMS and ‘a database’ in a strict viva.

DBMS

DBMS — sample query

Short notes

Questions

DBMS

DBMS — sample query

Short notes

Questions