Accessing Databases Using JDBC - Java Programming: Comprehensive Concepts and Techniques - page 720

given names. Such names typically use an identifier, such as PK for primary key
and FK for foreign key, along with the table name and one or more possible field
names. Table 11-6 lists some examples of constraints and their respective SQL
keywords.

Table 11-6 SQL Constraints

TYPE LEVEL EXAMPLE SQL KEYWORDS

Integrity Table PRIMARY KEY

Integrity Column FOREIGN KEY

Value Table UNIQUE

Value Column NOT NULL

Lines 68 through 104, as shown in Figure 11-17 on page 710, create the
Stocks and Users tables. Individual field names, types, sizes, and named con-
straints are listed within field declarations, which are separated by commas. The
tables are created by calling the executeUpdate() method, each within a separate
try block, allowing execution to continue even if any one table creation throws an
exception. Such an exception would occur if a table already exists. The following
steps enter code to create the Stocks and Users tables and primary key indexes.

To Create Tables with Primary Keys

1. Enter lines 68 through 86 as shown in Figure 11-17.
The SQL statement, CREATE TABLE, is used to create the Stocks table
(Figure 11-24). Following the table name is a comma-delimited list of fields,
types, sizes, and constraints within parentheses. The field, symbol, of type
TEXT with a maximum length of 8, has a value constraint of NOT NULL,
meaning it cannot have a null, or empty, value. It also is used as the pri-
mary key. The field, name, is of type TEXT with a maximum length of 50.

SQL statement
CREATE TABLE

table
name

fields,
types, sizes,
constraints

comma separates
field declarations

FIGURE 11-24