Quiz — 63da33a1434da__Série 3-Base de Donné.pdf

Question 1 sur 10 20:00

[{"id":44960,"question":"Quelle commande SQL permet d'ajouter un nouvel enregistrement dans une table ?","option_a":"INSERT INTO","option_b":"UPDATE","option_c":"DELETE","option_d":"SELECT","option_e":"","option_f":"","bonne_reponse":"a","explication":"La commande INSERT INTO est utilisée pour ajouter un ou plusieurs enregistrements dans une table existante.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"INSERT INTO\", \"b\": \"UPDATE\", \"c\": \"DELETE\", \"d\": \"SELECT\"}}","_debug_options_count":4},{"id":44961,"question":"Dans une table 'etudiants', l'attribut 'id' est défini comme clé primaire. Que se passe-t-il si on essaie d'insérer un enregistrement avec un 'id' déjà existant ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Faux. Une clé primaire doit être unique, donc l'insertion échouera car l'ID existe déjà (violation de la contrainte d'unicité).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":44962,"question":"Quelle requête permet de compter le nombre d'élèves dans une table 'eleves' ?","option_a":"SELECT COUNT(*) FROM eleves;","option_b":"SELECT * FROM eleves;","option_c":"SELECT SUM(*) FROM eleves;","option_d":"SELECT COUNT(eleves) FROM eleves;","option_e":"","option_f":"","bonne_reponse":"a","explication":"La requête SELECT COUNT(*) FROM eleves; compte le nombre total d'enregistrements dans la table 'eleves'.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"SELECT COUNT(*) FROM eleves;\", \"b\": \"SELECT * FROM eleves;\", \"c\":","_debug_options_count":4},{"id":44963,"question":"Quelle forme normale exige que chaque attribut non clé dépende entièrement de la clé primaire ?","option_a":"1FN","option_b":"2FN","option_c":"3FN","option_d":"BCNF","option_e":"","option_f":"","bonne_reponse":"b","explication":"La 2ème forme normale (2FN) exige que tous les attributs non clés dépendent entièrement de la clé primaire (pas de dépendance partielle).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"1FN\", \"b\": \"2FN\", \"c\": \"3FN\", \"d\": \"BCNF\"}}","_debug_options_count":4},{"id":44964,"question":"Dans une requête SQL, la clause WHERE est-elle obligatoire ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Faux. La clause WHERE est optionnelle. Elle est utilisée pour filtrer les résultats, mais une requête comme SELECT * FROM table; est valide.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":44965,"question":"Quelle commande permet de supprimer une table entière d'une base de données ?","option_a":"DROP TABLE","option_b":"DELETE TABLE","option_c":"REMOVE TABLE","option_d":"TRUNCATE TABLE","option_e":"","option_f":"","bonne_reponse":"a","explication":"La commande DROP TABLE supprime définitivement une table et toutes ses données de la base de données.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"DROP TABLE\", \"b\": \"DELETE TABLE\", \"c\": \"REMOVE TABLE\", \"d\": \"TRUN","_debug_options_count":4},{"id":44966,"question":"Quel type de jointure retourne toutes les lignes de la table de gauche, même si aucune correspondance n'existe dans la table de droite ?","option_a":"INNER JOIN","option_b":"LEFT JOIN","option_c":"RIGHT JOIN","option_d":"FULL JOIN","option_e":"","option_f":"","bonne_reponse":"b","explication":"LEFT JOIN (ou LEFT OUTER JOIN) retourne toutes les lignes de la table de gauche, avec les correspondances ou NULL si aucune correspondance n'existe.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"INNER JOIN\", \"b\": \"LEFT JOIN\", \"c\": \"RIGHT JOIN\", \"d\": \"FULL JOIN","_debug_options_count":4},{"id":44967,"question":"Dans une base de données normalisée, une table ne doit contenir que des attributs qui dépendent directement de la clé primaire.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai. C'est le principe de la 3ème forme normale (3FN) : tous les attributs non clés doivent dépendre uniquement de la clé primaire.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":44968,"question":"Quelle requête permet de trier les résultats d'une requête par ordre croissant de nom ?","option_a":"SELECT * FROM eleves ORDER BY nom ASC;","option_b":"SELECT * FROM eleves SORT BY nom;","option_c":"SELECT * FROM eleves GROUP BY nom;","option_d":"SELECT * FROM eleves WHERE nom ASC;","option_e":"","option_f":"","bonne_reponse":"a","explication":"La requête SELECT * FROM eleves ORDER BY nom ASC; trie les résultats par ordre alphabétique croissant du nom.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"SELECT * FROM eleves ORDER BY nom ASC;\", \"b\": \"SELECT * FROM elev","_debug_options_count":4},{"id":44969,"question":"Quel est l'avantage principal de l'utilisation d'index dans une base de données ?","option_a":"Réduire la taille de la base de données","option_b":"Accélérer les recherches sur les colonnes indexées","option_c":"Supprimer les doublons automatiquement","option_d":"Autoriser les requêtes parallèles","option_e":"","option_f":"","bonne_reponse":"b","explication":"Les index améliorent les performances des requêtes en permettant une recherche plus rapide sur les colonnes indexées.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Réduire la taille de la base de données\", \"b\": \"Accélérer les","_debug_options_count":4}]