单项选择题
A. It produces an error because data already exists in the table.
B. It produces an error because compression can be enabled at table creation only.
C. It compresses all data added or modified henceforth but the existing data in the table is not compressed immediately.
D. It immediately compresses all existing data as well as new data， resulting from either fresh additions or modifications to existing data.
单项选择题 In your production database, users report that they are unable to generate reports on an important table because it does not contain any data. While investigating the reason, you realize that another user executed the TRUNCATE TABLE command, which accidentally caused the data to be lost. Now you want to recover the lost data of the table without affecting objects in other schemas. Which method must you use to recover the lost data?（）
多项选择题 WhichtwostatementsabouttheSQLManagementBase（SMB）aretrue？（）
多项选择题 Which three functions are performed by the SQL Tuning Advisor?（） (Choose three.)