Consider a relational database for SpaceFace.com, a new social media site. The schemas of these relations (with primary key attributes underlined) are:

User-schema = (user_id, name,favorite_band_id)

Group-schema= (group_id, name, description, favorite_band_id)

Note-schema=(note_id, user_id, text)

BelongsTo-schema= (user_id, group_id, private)

InvitedTo-schema=(group_id,invitor_id,invitee_id)

Bands-schema= (band_id, name, genre)

Where:

Users can create notes, which are stored in the note relation. In addition, when a user joins agroup, a tuple is created in the belongsTo relation.

Relation Descriptions:

users lists all of the users of the site

group lists all of the groups on the site

note lists notes that a user all of the students of the college

belongsToindicates the group for which a user is a member

invitedToindicates pending invitations for a user

bands lists music bands

Attribute Descriptions:

user_id, group_id, note_id, and band_id are integers assigned to each user, group, and band, respectively

name is either the name of a user, group, or band (depending on the relation), and can be no more than 80 characters long

favorite_band_id is the band_id of a users or groups favorite band. Note that a user or group may not have a favority band.

invitor_id is the user_id of the person who invited someone to the group. This person must be a member of the group

invitee_id is the user_id of the person who has been invited to a group. This person will not yet be a member of the group.

description and text are strings of up to 255 characters

private is a variable that indicates whether the new members require an invitation from an existing member to join. Note that there is no Boolean domain in Oracle, so you can use char(1) instead.

Give SQL statements to create the six relations showed above.

Note:

List the statements in the order in which you would execute them.

Be sure to define appropriate primary keys and foreign key constraints.

Be sure to enforce as many of the constraints on the attributes as possible, given the constraints that we have discussed so far(not null, primary key, foreign key, unique, check).