IBM Data Server DB2 User Manual
Page 251
Chapter 5. Deploying pre-configured databases
237
Because our tables are empty, we choose the
insert
mode. In Example 5-15 we
show the statements to populate our sample database using the IXF files
exported in the previous section.
Example 5-15 Import statements used to populate our sample database
import from "dept.ixf" of ixf messages "dept.msg" insert into itso.department;
import from "emp.ixf" of ixf messages "emp.msg" insert into itso.employee;
import from "staff.ixf" of ixf messages "staff.msg" insert into itso.staff;
Because referential constraints are set during import, tables must be imported in
the right order. In our example, there is a foreign key relation from the
EMPLOYEE table to the DEPARTMENT table, therefore, we must import the
DEPARTMENT table before the EMPLOYEE table.
There are several other options that can be used to control the import utility. For
a thorough description, refer to the DB2 Infocenter:
Load utility
The load utility writes formatted pages directly into the database, which makes it
much faster then the import utility. The load utility does not perform referential
constraints or table constraint checking. The only validation performed is that the
uniqueness of the indexes. Like the import utility, different load modes are
available to control what to do with the existing data. For an initial load, we can
choose between
insert
or
replace
mode. Because our tables are empty, it makes
no difference which mode is chosen.
After load, the tables with constraints will be in the
integrity pending mode
and
cannot be accessed. You can use the
set integrity
command to check the
constraints and bring the table back to the accessible mode.
In our sample database we have a referential constraint defined between the
EMPLOYEE table to the DEPARTMENT table. After loading, the EMPLOYEE
table will be in the
integrity pending mode
because the foreign key relation has not
been checked. Furthermore, the summary table also has to be checked.
Example 5-16 shows the load statements and the required check statements to
populate our database and make the tables accessible.
Example 5-16 The load and integrity check statements for our sample database
load from "emp.ixf" of ixf messages "emp.msg" insert into itso.employee copy no
indexing mode autoselect;
load from "dept.ixf" OF ixf messages "dept.msg" insert into itso.department
copy no indexing mode autoselect;