A teacher ID field is set as a PRIMARY KEY. What does this constraint enforce?, Each teacher must have a unique ID, The field must contain text only, The field cannot store numbers, The field must be left empty by default, A bank transfers €500 from Account A to Account B. Midway through, the system crashes. What should happen?, Account A loses €500 and Account B receives nothing, Both accounts receive the amount, The whole transaction is rolled back, The transaction is automatically retried immediately, Which integrity method would automatically log a record to an audit table every time a customer is deleted?, Constraint, Trigger, Transaction, Validation rule, Why should a contact number field use the Text data type rather than Number?, Numbers are harder to store in a database, Text fields are faster to search, Text fields take up less storage space, No arithmetic calculations on contact numbers

Databases: Data Integrity 2

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