Lesson 6 Flashcards

1
Q

alias

A

An alternative name for a column or table in a SQL statement.

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2
Q

ALTER TABLE

A

The SQL command used to make changes to table structure. When the command is followed by a keyword (ADD or MODIFY), it adds a column or changes column characteristics.

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3
Q

AND

A

The SQL logical operator used to link multiple conditional expressions in a WHERE or HAVING clause. It requires that all conditional expressions evaluate to true.

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4
Q

AVG

A

A SQL aggregate function that outputs the mean average for a specified column or expression.

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5
Q

BETWEEN

A

In SQL, a special comparison operator used to check whether a value is within a range of specified values.

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6
Q

Boolean algebra

A

A branch of mathematics that uses the logical operators OR, AND, and NOT.

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7
Q

cascading order sequence

A

A nested ordering sequence for a set of rows, such as a list in which all last names are alphabetically ordered and, within the last names, all first names are ordered.

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8
Q

COMMIT

A

The SQL command that permanently writes data changes to a database.

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9
Q

COUNT

A

A SQL aggregate function that outputs the number of rows containing not null values for a given column or expression, sometimes used in conjunction with the DISTINCT clause.

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10
Q

CREATE INDEX

A

A SQL command that creates indexes on the basis of a selected attribute or attributes.

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11
Q

CREATE TABLE

A

A SQL command that creates a table’s structures using the characteristics and attributes given.

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12
Q

DELETE

A

A SQL command that allows data rows to be deleted from a table.

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13
Q

DISTINCT

A

A SQL clause that produces only a list of values that are different from one another.

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14
Q

DROP INDEX

A

A SQL command that permanently deletes an index.

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15
Q

DROP TABLE

A

A SQL command that permanently deletes a table and its data.

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16
Q

EXISTS

A

In SQL, a comparison operator that checks whether a subquery returns any rows.

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17
Q

FROM

A

A SQL clause that specifies the table or tables from which data is to be retrieved.

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18
Q

GROUP BY

A

A SQL clause used to create frequency distributions when combined with any of the aggregate functions in a SELECT statement.

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19
Q

HAVING

A

A clause applied to the output of a GROUP BY operation to restrict selected rows.

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20
Q

IN

A

In SQL, a comparison operator used to check whether a value is among a list of specified values.

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21
Q

inner query

A

A query that is embedded or nested inside another query. Also known as a nested query or a subquery.

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22
Q

INSERT

A

A SQL command that allows the insertion of one or more data rows into a table.

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23
Q

IS NULL

A

In SQL, a comparison operator used to check whether an attribute has a value.

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24
Q

LIKE

A

In SQL, a comparison operator used to check whether an attribute’s text value matches a specified string pattern.

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25
Q

MAX

A

A SQL aggregate function that yields the maximum attribute value in a given column.

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26
Q

MIN

A

A SQL aggregate function that yields the minimum attribute value in a given column.

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27
Q

nested query

A

In SQL, a query that is embedded in another query.

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28
Q

NOT

A

A SQL logical operator that negates a given predicate.

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29
Q

OR

A

The SQL logical operator used to link multiple conditional expressions in a WHERE or HAVING clause. It requires only one of the conditional expressions to be true.

30
Q

ORDER BY

A

A SQL clause that is useful for ordering the output of a SELECT query (for example, in ascending or descending order).

31
Q

ROLLBACK

A

A SQL command that restores the database table contents to the condition that existed after the last COMMIT statement.

32
Q

rules of precedence

A
  • Basic algebraic rules that specify the order in which operations are performed.
  • For example, operations within parentheses are executed first, so in the equation 2 + (3 * 5), the multiplication portion is calculated first, making the correct answer 17.
33
Q

subquery

A

A query that is embedded (or nested) inside another query. Also known as a nested query or an inner query.

34
Q

SUM

A

A SQL aggregate function that yields the sum of all values for a given column or expression.

35
Q

UPDATE

A

A SQL command that allows attribute values to be changed in one or more rows of a table.

36
Q

WHERE

A

A SQL clause that adds conditional restrictions to a SELECT statement that limit the rows returned by the query.

37
Q

wildcard character

A

A symbol that can be used as a general substitute for: (1) all columns in a table (*) when used in an attribute list of a SELECT statement or, (2) zero or more characters in a SQL LIKE clause condition ( % and _ ).

38
Q

SQL commands can be divided into two overall categories: _______ and ______ commands.

A
  • Data definition languauge (DDL)

- Data manipulation language (DML)

39
Q

The basic DML commands are:

A
  • SELECT
  • INSERT
  • UPDATE
  • DELETE
  • COMMIT
  • ROLLBACK
40
Q

The basic data definition commands allow you to create tables and indexes. Many SQL constraints can be used with columns. The commands are:

A
  • CREATE TABLE
  • CREATE INDEX
  • ALTER TABLE
  • DROP TABLE
  • DROP INDEX
41
Q

The ANSI prescribes a standard SQL-the current fully approved version is known as SQL 07. (T/F)

A

False

42
Q

You can select partial table contents by naming the desired fields and by placing restrictions on the rows to be included in the output. (T/F)

A

True

43
Q

The ______ command, coupled with appropriate search conditions, is an incredibly powerful tool that enables a user to transform data into information.

A

SELECT

44
Q

The conditional LIKE should be used in conjunction with wildcard characters. (T/F)

A

True

45
Q

A database language enables the user to perform complex queries designed to transform the raw data into useful information. (T/F)

A

True

46
Q

The special operator used to check whether a subquery returns any rows is _____.

A

EXISTS

47
Q

According to the rules of precedence, which of the following computations should be completed first?

A

Performing operations within parentheses

48
Q

The SQL command that allows a user to permanently save data changes is _____.

A

COMMIT

49
Q

In SQL, all _______ expressions evaluate to true or false.

A

conditional or boolean

50
Q

A database language enables the user to create database and table structures to perform basic data management chores. (T/F)

A

True

51
Q

The SQL data manipulation command HAVING:

A

restricts the selection of grouped rows based on a condition.

52
Q

String comparisons are made from left to right. (T/F)

A

True

53
Q

To make the output more readable, the SQL standard permits the use of aliases for any column in a ______ statement.

A

SELECT

54
Q

Which operator is used to check whether an attribute value lies within two bounds?

A

BETWEEN

55
Q

The SQL command that allows a user to list the contents of a table is _____.

A

SELECT

56
Q

Date procedures are often more software-specific than other SQL procedures. (T/F)

A

True

57
Q

A _______ order sequence is a multilevel ordered sequence that can be created easily by listing several attributes, separated by commas, after the ORDER BY clause.

A

cascading

58
Q

Oracle users can use the Access QBE (query by example) query generator. (T/F)

A

False

59
Q

The _____ special operator is used to check whether an attribute value is null.

A

IS NULL

60
Q

SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT. (T/F)

A

True

61
Q

ANSI-standard SQL allows the use of special operators in conjunction with the WHERE clause. (T/F)

A

True

62
Q

The basic SQL vocabulary has fewer than _____ words.

A

hundred

63
Q

The ANSI SQL standards are also accepted by the ISO. (T/F)

A

True

64
Q

SQL is considered difficult to learn; its command set has a vocabulary of more than 300 words. (T/F)

A

False

65
Q

Mathematical operators cannot be used to place restrictions on character-based attributes. (T/F)

A

False

66
Q

A specialty field in mathematics, known as ______ algebra, is dedicated to the use of logical operators.

A

Boolean

67
Q

A(n) _____ is an alternate name given to a column or table in any SQL statement.

A

alias

68
Q

The SQL command that allows a user to insert rows into a table is _____.

A

INSERT

69
Q

The special operator used to check whether an attribute value matches a given string pattern is _____.

A

LIKE

70
Q

Most SQL implementations yield case-insensitive searches. (T/F)

A

False

71
Q

Some RDBMSs, such as Microsoft Access, automatically make the necessary conversions to eliminate case sensitivity. (T/F)

A

True

72
Q

In the SQL environment, the word _____ covers both questions and actions.

A

query