Consider the relational schema of an online social networking site depicted below. Every user has an...

 

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Consider the relational schema of an online social networking site depicted below. Every user has an integer ID, and a textual Status field. Users can follow other users (e.g., like Twitter). If U is the source user, and V is the destination user; then we say "U follows V". User ID Status Follows Source Destination (a) Draw the ER diagram of this relation schema. (b) In relational algebra, select the statuses of users satisfying low < ID < high. (c) In relational algebra, select the statuses of all users followed by source user usr. (d) In SQL, select the statuses of all users followed by source user usr. (e) In SQL, select the statuses of all distinct users followed by a follower of user usr. Do not bother excluding usr from the result. Consider the relational schema of an online social networking site depicted below. Every user has an integer ID, and a textual Status field. Users can follow other users (e.g., like Twitter). If U is the source user, and V is the destination user; then we say "U follows V". User ID Status Follows Source Destination (a) Draw the ER diagram of this relation schema. (b) In relational algebra, select the statuses of users satisfying low < ID < high. (c) In relational algebra, select the statuses of all users followed by source user usr. (d) In SQL, select the statuses of all users followed by source user usr. (e) In SQL, select the statuses of all distinct users followed by a follower of user usr. Do not bother excluding usr from the result.