-- Mar 17 In-Class Exercise

USER(USER_ID, USERNAME, EMAIL, PASSWORD) POST(POST_ID, USERID, POST, POPULARITY) USER_ID → USERNAME, EMAIL, PASSWORD POST_ID → USERID, POST, POPULARITY My tables are in BCNF

-- Mar 17 In-Class Exercise

users(user_id, username, email, password) post(post_id, user_id, post, likes) user_id -> username, email, password post_id -> user_id, post, likes These tables are in BCNF

-- Mar 17 In-Class Exercise

 Functional dependencies:
 USERID, PASSWORD--> USERNAME, EMAIL
 POST--> USERID, PCONTENT, PTIME, PPOPULARITY.

 Tables:
 USER(USERID, PASSWORD, USERNAME, EMAIL)
 POST(USERID, POST, PCONTENT, PTIME, PPOPULARITY)

 My tables are in BCNF because the left elements fix the rest elements.
 For the USER table, if we know USERID and PASSWORD, we know USERNAME and EMAIL.
 For the POST table, if we know POST, we know USERID, PCONTENT, PTIME, and PPOPULARITY.

Functional dependencies: USERID, PASSWORD--> USERNAME, EMAIL POST--> USERID, PCONTENT, PTIME, PPOPULARITY. Tables: USER(USERID, PASSWORD, USERNAME, EMAIL) POST(USERID, POST, PCONTENT, PTIME, PPOPULARITY) My tables are in BCNF because the left elements fix the rest elements. For the USER table, if we know USERID and PASSWORD, we know USERNAME and EMAIL. For the POST table, if we know POST, we know USERID, PCONTENT, PTIME, and PPOPULARITY.

-- Mar 17 In-Class Exercise

<nowiki> -------------------------------------- Types -------------------------------------- UID string USERNAME string EMAIL string PW string PID int TEXT string UPVOTES int -------------------------------------- Functional Dependencies -------------------------------------- UID --> USERNAME, PW, EMAIL PID --> UID, TEXT, UPVOTES -------------------------------------- Tables -------------------------------------- USER(UID, USERNAME, EMAIL, PW) POST(PID, UID, TEXT, UPVOTES) -------------------------------------- Reasoning -------------------------------------- The tables are BCNF because knowing the UID in the USER table will fix the entire row: USERNAME, EMAIL, and PW, and knowing the PID in the POST table will resolve the row containing UID, TEXT, and UPVOTES.</nowiki>

-- Mar 17 In-Class Exercise

USERS(USERID, USERNAME) POSTS(POSTID, USERID, CONTENT, POPULARITY) USERID -> USERNAME POSTID -> USERNAME, CONTENT, POPULARITY

-- Mar 17 In-Class Exercise

USER(USERID, EMAIL, PASSWORD, USERNAME) POST(POSTID, USERID, LIKES, POSETDESC) functional dep: USERID -> EMAIL, PASSWORD, USERNAME POSTID -> USERID, LIKES, POSTDESC