【单选题】What is the candidate key of a relational database? ( )
A.
Fields from multiple tables that are used for sorting records
B.
A set of fields in a table used to identify a record uniquely
C.
A field with a constraint placed on it
D.
A set of fields that have no data in them
【简答题】combine the sentences in each of the following groups into one, using parallel constructions wherever possible. A Black people in America have been neglected for years B Black people in America have b...
【单选题】流清涕和鼻黏膜肿胀,无明确的吸入过敏原,有个人过敏性疾病史,变应原皮肤试验两项阳性,特异性IgE抗体检测阴性,鼻分泌物涂片检查嗜酸性粒细胞阴性。该患者的诊断是
【单选题】Customer relationship management systems typically provide software and online tools for sales, customer service, and
【单选题】Which of the following is a logical connected set of fields that describes a person, place or a thing?
【简答题】A Black people in America have been neglected for years B Black people in America have been underestimated for years C. Their recent accomplishments in a variety of fields have made "black power"real。...
【单选题】思科路由器上全局配置模式的提示符是什么?
【判断题】A bunch of fields form a record
【单选题】Customer relationship management systems typically provide software and online tools for sales, customer service, and