1.a Table field M Insert a maximum value of the current field to add a maximum value of the current field, add a suitable database object or data type and write SQL Create Sequence Secrement by Creating Database objects or types, SQL Create Sequence Secrement by 1 Start With 1 ManValue 999999999 Cycle; 2. Describe the reasons for the concept of the concept of locks in the database View and lock SQL 3. Connect the unique index of the table A m and n fields. CREATE UNIQUE INDEX T_B_INDEX2 ON T_B (C, E)
