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1、互联网数据库（Internet Database）The basis of the 1.1 relational calculus is (C)Logic calculus in a formal logic; relational calculus in formal logic; predicate calculus in C mathematical logic; formal calculus in B mathematical logic D1.2, a description of the logical structure and characteristics of globa
2、l data is called (C)A external mode, B internal mode, C mode, D storage mode1.3 when SUM (column name) is used in the SELECT statement, the column name request (A) is usedA must be numeric. B must be character type. C must be numeric or character type. D does not restrict data type. Only numeric val
3、ue can be used for summing operations.1.4E-R model design belongs to the database (A)A concept design, B logic design, C physics design, D programming1.5 a description of the physical structure and storage of data in a database is called (B)A external mode, B internal mode, C mode, D storage modeIn
4、1.6SQL language, the operation of recovering the authorization limit is realized by (D) statement.AGRANT bSELECT cUPDATE dREVOKE parse A grant authority, B as selection, C update data, D grant authority for recovery1.7, if you want to modify the structure of the table, the SQL statement you should u
5、se is DA, UPDATETABLE, B, MODIFYTABLE, C, CHANGETABLE, D, ALTERTABLEThe 1.8 data model has three elements, for which the static characteristics of the system are described (A)A data structure, B data manipulation, C data integrity constraint, D data retrieval1.9 a data model that uses two-dimensiona
6、l tables to represent the relation between entities and entities is called (C)AE-R model, B hierarchical model, C relation model, D mesh model1.10 the following description is correct (D)ASQL is a procedural language, and bSQL can not be embedded into high-level language programs. CSQL is a DBMSdSQL
7、 and uses assembly operations1.11 in the basic operation of a relational database, an operation that selects a record that satisfies a given condition from the table is called (A)A selects the B projection, C connections, and D scans1.12 in the following statement about tuples, variables, and relati
8、onships, the correct one is (B)A a relationship can only have a tuple variable B, a relationship can have multiple tuple variables, C, a relationship must have more than one tuple variable, and the D relationship cannot set tuple variables1.13 which relation does the database use to represent the re
9、lation between entities? (C)A tree structure, B net structure, C two-dimensional table, D linear tableIn the following 1.14, the set function provided by SQL is not (C)A, COUNT, B, AVG, C, TRUNC, D, MAX parse TRUNC is the intercept function.The 1.15 known three relationships: students (student numbe
10、r, name, gender) course (course number, course name, course grades) (student number, course number, fraction) to list the elective course named DB, and the score is lower than the students name and score 60, relational algebra operations should be used with (A)A selection, projection, natural connec
11、tion, B selection, projection, C selection, natural connection, D projection, and natural connection1.16 in SQL, the SELECTDISTINCT of the SELECT statement represents the result of the query (B)The a attribute names are not the same. B removes duplicate columns. The C attribute values are different.
12、 The D rows are not the same. parse no duplicate columns are included in the SELECTDISTINCT1.17 the correct item in the following statement about the view is (B)A to prevent users through the data add, delete, view, unintentional or intentional operation does not belong to the basic data to range, c
13、an be defined in view with withcheckstrickb view on the reconstruction of the database provides a certain degree of logical independence while C view simplifies users operation, but did not provide for confidential data to protect the safety of D can be indexed in the view1.18, the SQL statement use
14、d to implement data access security control is (D)A, CREATEINDEX, B, COMMIT, C, ROLLBACK, D, GRANT, and REVOKEThe ALPHA language proposed by 1.19E.F.Codd is (A)A a typical tuple relational calculus Language B, a typical logical relational calculus language C, a typical domain relational calculus lan
15、guage, D, is a typical form of relational calculus language1.20 the following statement about clustered indexes is correct (A)A in a basic table can only create a clustered index B in a basic form to create a number of cluster index C only in a basic form of less than the basic table records the num
16、ber of clustered index D in a basic form up to establish equal to the number of the cluster index the basic record table1.21, the integrity rule of the relational model is a constraint to the relation. In the relational model, there are three kinds of holonomic constraints, which are called the two invariants of the relation
