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Create a Database Management System

HardSQL · PostgreSQL00:00
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Your question is Create a Database Management System. Start with the requirements and the four tables on the right.

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Problem

Create a database management system.

Implement the PostgreSQL data model and write a query that produces an administrative summary for every managed database. Include databases with no members or audit events, and treat revoked memberships as inactive.

Output

  1. One row per managed database with database_name, owner_name, active_member_count, audit_event_count, latest_event_type, and latest_event_at.
  2. Include databases without an owner, members, or events using NULL or zero values as appropriate.
  3. Order by database_name ascending.

Schema

managed_databases
ColumnTypeDescription
database_idPKINTUnique managed database identifier
database_nameVARCHAR(100)Display name of the managed database
owner_user_idINTUser responsible for the database
created_atTIMESTAMPDatabase creation timestamp
database_users
ColumnTypeDescription
user_idPKINTUnique user identifier
display_nameVARCHAR(100)User display name
emailVARCHAR(255)User email address
database_memberships
ColumnTypeDescription
membership_idPKINTUnique membership identifier
database_idINTManaged database identifier
user_idINTMember user identifier
roleVARCHAR(30)Membership role
granted_atTIMESTAMPMembership grant timestamp
revoked_atTIMESTAMPMembership revocation timestamp
audit_events
ColumnTypeDescription
event_idPKINTUnique audit event identifier
database_idINTDatabase associated with the event
user_idINTUser who caused the event
event_typeVARCHAR(40)Type of audited activity
event_atTIMESTAMPEvent occurrence timestamp
Tablesmanaged_databasesdatabase_usersdatabase_membershipsaudit_events
Your solutionPostgreSQL
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