A. Delete * from emp B. Drop table emp C. Drop * from emp D. delete database emp
A. Latin1 B. Utf8mb4 C. GBK D. GB2312
A. FIND B. SELETE C. ALTER DESC
A. INT B. CHAR C. VARCHAR D. BINARY
A. 创建唯一的索引,允许空值 B. 只允许以表中第一字段建立 C. 允许有多个主键的 D. 标识表中实体的唯一性