Chemistry Reference
In-Depth Information
Table 2.1
Sample Table of Chemical Compound Data from EPA
Name
Formula
MW
logP
MP
Formaldehyde
CH
2
O
30.03
0.35
−92
Guanidine hydrochloride
CH
6
ClN
3
95.53
−3.56
182.3
Dexamethasone
C
22
H
29
FO
5
392.47
1.83
262
Cortisone acetate
C
23
H
30
O
6
402.49
2.1
222
Phenobarbital
C
12
H
12
N
2
O
3
232.24
1.47
174
Oxyphenonium bromide
C
21
H
34
BrNO
3
428.41
0.17
191.5
Metharbital
C
9
H
14
N
2
O
3
198.22
1.15
150.5
Mesantoin
C
12
H
14
N
2
O
2
218.26
1.69
135
Meperidine
C
15
H
22
ClNO
2
283.80
3.03
187.5
Vitamin D2
C
28
H
44
O
396.66
10.44
116.5
Client programs are discussed in later chapters of this topic. The struc-
tured query language (SQL) designed for creating, selecting, deleting, and
updating the database is discussed in Chapter 3.
A relational table has a name, chosen when it is created. Although any
name is possible, the name typically reflects the nature or source of the
data contained in the table. Each column must also have a name. Consider
Table 2.1, called EPA since it was constructed from data provided by the
Environmental Protection Agency.
2
This table is readily understandable
to any chemist. Each row contains information about one compound and
each column contains a molecular attribute or property. In order to make
it part of a relational database, a minimum of two things must be speci-
fied for each column: the column name and the column data type. In this
example, the column names are Name, Formula, MW, logP, and MP corre-
sponding to the compound name, molecular formula, molecular weight,
octanol-water partition coefficient, and melting point. The column name
in a relational table is arbitrary but is usually representative of the data
contained in the column.
The nature of the data in each column must be specified by providing
a data type. The data type must be one of a fixed set of types available
in the relational database management system (RDBMS) being used. A
discussion of several common RDBMS follows in Chapter 4. Some of the
frequently used data types are
•
Integer for whole numbers
•
Numeric for possibly fractional numbers
•
Text for character strings
•
Date for dates
•
Time for time-of-day values
•
Timestamp for values containing both date and time
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