Справочник Пользователя для IBM 000-8697
4-54
IBM Informix OnLine Database Server Administrator’s Guide
Description of Migration Methods
Description of Migration Methods
This section provides an overview of how each data migration method
works.
works.
illustrates the four migration methods. This
section does not attempt to compare the methods. Comparisons and
contrasts begin on
contrasts begin on
.
Refer to
for a complete discussion of each OnLine
utility. The
LOAD
and
UNLOAD
statements are documented the
DB
-
A
ccess
U
ser’s
M
anual.
UNLOAD/dbschema/LOAD
The
DB-A
ccess
UNLOAD
statement writes the rows retrieved in a SELECT
statement to a delimited ASCII file. A parameter in the
UNLOAD
statement
enables you to specify a field-delimiting character for the
ASCII
file. The
UNLOAD
statement creates the ASCII input file of migration data.
The database server utility dbschema writes the
SQL
statements needed to
replicate the specified database or table to an ASCII file. The dbschema
output file can be modified with a system editor or run as is to create the
database or table that will receive the migration data.
output file can be modified with a system editor or run as is to create the
database or table that will receive the migration data.
The
DB-A
ccess
LOAD
statement inserts data from one or more of the
delimited
ASCII
input files created by
UNLOAD
into one or more tables
created from a dbschema output file.
UNLOAD/dbschema/dbload
The
UNLOAD
statement and dbschema utility perform the same preparation
tasks in this method as described in the preceding paragraph. The database
server utility dbload takes one or more
server utility dbload takes one or more
ASCII
input files created by
UNLOAD
and inserts the data into one or more specified tables created from a
dbschema
dbschema
output file. The dbload utility inserts the data as directed by a
command file that is created by the user. The user can specify additional
instructions at the command line when dbload is executed.
instructions at the command line when dbload is executed.