Acandidate key is(). A.an attribute or a set of attributes with a unique value for each tuple of a relationB.a set of attributes referring to another relation in the databaseC.an attribute or a set of attributes that is potentially the primary key of a relationD.an attribute or a set of attributes that is potentially(有潜力地)the super key(超键)of a relation
Acandidate key is().
A.an attribute or a set of attributes with a unique value for each tuple of a relation
B.a set of attributes referring to another relation in the database
C.an attribute or a set of attributes that is potentially the primary key of a relation
D.an attribute or a set of attributes that is potentially(有潜力地)the super key(超键)of a relation
相关考题：
Python中通过Key来从字典object中读取对应的Value的方法有() A.object[key]B.object.get(key)C.object.pop(key)D.object.pop()
_____, the boy couldn’t get into his dorm.A. Since the key lostB. The key having lostC. Lost the keyD. Having lost the key
In a public-key cryptosystem,(71)encrypted with the public key can only be deciphered with the private key from the same(72). Conversely,(71)encrypted with the private key can be decrypted only with the public key. Users can make their public keys(73)available or place them at a key distribution center or others to access. However, the private key must be(74)safe. In public-key systems there's no(75)to find a safe channel for communicating a shared secret key.A．binarytextB．hypertextC．plaintextD．supertext
Symmetric, or private-key, encryption is based on a secret key that is shared by both communcating parties. The （ ） party uses the secret key as part of the mathematical operation to encrypt （ ） text to cipher text. The receiving party uses the same secret key to decrypt the cipher text to plain text. Asymmetric, or public-key, encryption uses two different keys for each user: one is a （ ） key known only to this one user; the other is a corresponding public key, which is accessible to anyone. The private and public keys are mathematically related by the encryption algorithm. One key ia used for encyption and the other for decryption, depending on the nature of the communication service being implemented. In addition, public key encryption technoligies allow digital （_______） to be placed on messages. A digital signature uses the sender's private key to encrypt some portion of the message. When the message is received, the receiver uses the sender's （） key tp decipher the digital signature to verify the sender's identity.横线处应选（ ）。 A. interpretationB.signaturesC. encryptionD.decryption
键盘事件的执行顺序是（）。AKey Press、Key Down、Key UpBKey Down、Key Press、Key UpCKey Up、Key Down、Key PressDKey Up、Key Press、Key Down
Usually low key is used for emphasis and contrast; mid key indicates an expected, neutral attitude; and low key provides low information.（）
By default， what type of SSH server key is generated by Cisco NX-OS Software？（）A、 DSA key generated with 512 bitsB、 RSA key generated with 768 bitsC、 RSA key generated with 1024 bitsD、 DSA key generated with 1024 bitsE、 RSA key generated with 2048 bits
Which statement is true regarding a session key in the Diffie-Hellman key-exchange process?（）A、A session key value is exchanged across the network.B、A session key never passes across the network.C、A session key is used as the key for asymmetric data encryption.D、A session key is used as the key for symmetric data encryption.
键盘事件的执行顺序是（）。A、Key Press、Key Down、Key UpB、Key Down、Key Press、Key UpC、Key Up、Key Down、Key PressD、Key Up、Key Press、Key Down
假设d为一个空字典d={}。以下语句中执行后，d的内容将会变为{’key’：1}：（）A、d[’key’]=1B、d.update（’key’=1）C、d.setdefault（’key’，1）D、d.update（key=1）
判断某个key是否在字典d中存在，以下做法正确且严谨的是：（）A、’key’ind.keys（）B、d.get（’key’）isnotNoneC、hasattr（d，’key’）D、’key’ind
要在session对象中保存属性，可以使用以下哪个语句？（）A、session.getAttribute（“key”,”value”）B、session.setAttribute（“key”,”value”）C、session.setAtrribute（“key”）D、session.getAttribute（“key”）
Which two statements about the Diffie-Hellman （DH） key exchange process are correct？（）A、In the DH key exchange process， the session key is never passed across the network.B、In the DH key exchange process， the public and private keys are mathematically related using the DH algorithm.C、In the DH key exchange process， the session key is passed across the network to the peer for confirmation.D、In the DH key exchange process， the public and private keys are not mathematically related， ensuring higher security
Which two statements are true about the primary key constraint in a table？ （）A、It is not possible to disable the primary key constraint.B、It is possible to have more than one primary key constraint in a single table.C、The primary key constraint can be referred by only one foreign key constraint.D、The primary key constraint can be imposed by combining more than one column.E、The non-deferrable primary key constraint creates an unique index on the primary key column if it is not already indexed.
PKI的全称是（）。A、Private Key IntrusionB、Public Key IntrusionC、Private Key InfrastructureD、Public Key Infrastructure
单选题The RSA algorithm is an example of what type of cryptography?RSA算法是下面哪种算法的典型例子？（）APrivate Key.私钥BSymmetric Key对称密钥CSecret Key秘密密钥DAsymmetric Key.非对称密钥
单选题By default， what type of SSH server key is generated by Cisco NX-OS Software？（）A DSA key generated with 512 bitsB RSA key generated with 768 bitsC RSA key generated with 1024 bitsD DSA key generated with 1024 bitsE RSA key generated with 2048 bits
单选题PKI是（）。APrivate Key lnfrastructureBPublic Key lnstituteCPublic Key lnfrastructureDPrivate Key lnstitute
多选题DPM812错误H2（发KEY掉落失败）故障可能原因（）A落点处有KEY，KEY架起而没有压倒落点的传感器说明KEY盒尺寸超差，或发KEY档片未安装B落点处的KEY平整的置于通道内，说明落点处的传感器失灵C导向轴与轴套干或有异物D落点处无KEY说明发KEY推杆未推出KEY
单选题PKI是（）。APrivate Key InfrastructureBPublic Key InstituteCPublic Key Infrastructure公钥基础设施DPrivate Key Institute
单选题键盘事件的执行顺序是（）。AKey Press、Key Down、Key UpBKey Down、Key Press、Key UpCKey Up、Key Down、Key PressDKey Up、Key Press、Key Down
多选题Which two statements are true about the primary key constraint in a table？ （）AIt is not possible to disable the primary key constraint.BIt is possible to have more than one primary key constraint in a single table.CThe primary key constraint can be referred by only one foreign key constraint.DThe primary key constraint can be imposed by combining more than one column.EThe non-deferrable primary key constraint creates an unique index on the primary key column if it is not already indexed.
单选题Which statement is true regarding a session key in the Diffie-Hellman key-exchange process?（）AA session key value is exchanged across the network.BA session key never passes across the network.CA session key is used as the key for asymmetric data encryption.DA session key is used as the key for symmetric data encryption.
多选题Which two statements about the Diffie-Hellman （DH） key exchange process are correct？（）AIn the DH key exchange process， the session key is never passed across the network.BIn the DH key exchange process， the public and private keys are mathematically related using the DH algorithm.CIn the DH key exchange process， the session key is passed across the network to the peer for confirmation.DIn the DH key exchange process， the public and private keys are not mathematically related， ensuring higher security
多选题Which two statements about the Diffie-Hellman (DH) key exchange process are correct? （）(Choose two.)AIn the DH key exchange process, the session key is never passed across the network.BIn the DH key exchange process, the public and private keys are mathematically related using the DH algorithm.CIn the DH key exchange process, the session key is passed across the network to the peer for confirmation.DIn the DH key exchange process, the public and private keys are not mathematically related, ensuring higher security