If a table satisfies a FD A ? B (where A,B are sets of attributes), then no two rows of the table that have the same values for the attributes in A can have the same values for the attributes in B. (True / False)
Yes, A functional dependency A->B in a relation holds if two tuples having same value of attribute A alsohave same value for attribute B.
False
If a table satisfies a FD A ? B (where A,B are sets of attributes), then...
Given the following Schema S = (R, FD) where R = (A, B, C, D, E, F) and FD contains the following dependencies: A -> BC B ->C C -> D D ->E C -> E E -> F DE -> F C -> F 1. Find a minimal cover of F 2. Find a key for the schema 3. Find a 3N decomposition of the schema that satisfies the lossless join decomposition and dependency preservation properties 4. Find a...
Question 16 Data sets can have more than one median a. True b. False Question 17 The median divides the data set, sequentially, by values below and values above the mode a. True b. False Question 18 This measure of central tendency provides the arithmetic average a. mode b. median c. mean d. distribution Question 19 Nominal data can be measured using the mean a. True b. False Question 20 The median represents the 50th percentile of a data set...
I would prefer 34. being answered
33. For the big order database table, list FDs with the column CustNo as the determinant that are not true due to the sample data. For each FD, identify the sample rows that contradict it. Remember that it takes two rows to contradict an FD. The sample data are repeated in Table 7-P4 for your reference Table 7-P4: Sample Data for the Big Order Database Table OrdNo temNo atyOrd PlantNo CustNo CustBa CustDisc ReordPt...
True or false
The WHERE clause of the DELETE command is used to identify the rows to be deleted from the table? If the WHERE clause of the DELETE command is omitted, then all rows in the referenced table will be removed? If a user has a shared block on a table, this will prevent any other user from obtaining a shared or exclusive lock on the same table?
Mark True/False for functional dependencies of the following table R(A, B, C, D, E), where we assume that it is the intent of the designer that exactly this set of rows should list in the table. A B C D E a1 b1 c1 d1 e1 a2 b2 c2 d2 e2 a1 b1 c1 d1 e2 a2 b2 c3 d4 e2 (a) A --> B (b) B --> A (c) C--> A (d) D --> A (e) CD --> B
Find the size of the concept space and sample space with 10 attributes. Assume each attribute can only take TRUE or FALSE values.
17-26
true or false questions
17. The smallest positive real number is c, where c = card(0,1). 18. To show that two sets A and B are equal, show that x A and x B. 19. If (vx)P(e) is false, then P(x) is never true for that domain. 20. If R is a relation on A and if (a, a) is true for some a in A, then R is reflexive. 21. If f:A → B is a function, then...
Consider the relation R with four attributes ABCD. For each of the two following sets of FDs, determine whether or not the R would be in BCNF, and if it is not, then decompose it into BCNF, and prove the result would produce a lossless join. 1. A → B,BC → D, A →C 2. AB → C,AB → DC → A, D + B
a. Every matrix equation Ax b corresponds to a vector equation with the same solution set. Choose the correct answer below. O A. False. The matrix equation Ax-b does not correspond to a vector equation with the same solution set. O B. False. The matrix equation Ax b only corresponds to an inconsistent system of vector equations. O c. True. The matrix equation Ax-bis simply another notation for the vector equation x1a1 + x2a2 +·.. + xnan-b, where al ,...
In the normalization process, you begin with a “table” in the form of a “relation”. Which of the following makes a “table” into the academic definition of a “relation”. A. Rows contain data about an entity. B. Each column has a unique name. C. All entries in a column are of the same kind – domain constraints D. The order of the columns is unimportant. E. No two rows may be identical. F. Columns contain data about attributes of the...