The Extract Process selects data from a source (one or
more tables in a database) and copies that data to a destination (an
Extract File).
To extract data, you must create an Extract Request
that includes the specifications for the data to be extracted, called
the Access Definition, and the parameters for the Extract Process.
You can process the Extract Request immediately, or schedule the process
to run automatically. You can also run the Extract Process from the
command line, using overrides for specifications in the request.
Extract Request
The Extract
Request Editor dialog allows you to select parameters for
processing the Extract Request. These parameters include the following:
- The Extract File, Access Definition, row limit,
and items to extract: data, objects (metadata), or both.
- Types of objects to extract: primary keys, relationships,
indexes, aliases/synonyms, functions, defaults, UDTs, packages, procedures,
sequences, triggers, views, and/or rules. (Move always extracts table
and column definitions.)
You can choose to run the Extract Request immediately
or schedule the request for later processing.
Extract File
The
Extract File contains the selected relationally intact data, the object
definitions, or both. The Extract File is stored locally on the client
system or on a shared file server. After you create an Extract File,
you can use the file as often as needed to create new, or refresh
existing, databases.
After you have extracted
data and created an Extract File, you can browse the contents of the
file. This is useful to ensure that the contents are as expected.
Access Definition
The
Access Definition governs the overall Extract Process. An Access Definition
specifies the tables, relationship traversal, and selection criteria
for the data you want to extract. You can select a named Access Definition
or create a new Access Definition for a single Extract Request.
The Access Definition enables you to:
- Specify the set
of tables to be included in the Extract Process. You can specify the
name of a single table and request that Move provide the names of
all related tables. One table is identified as the Start Table, or
table from which data is first extracted.
- Select relationships to be traversed to extract
the data. Move has default rules for how relationships are traversed
between the specified tables. You can select from a list of all of
the relationships defined to the database and to the Optim™ Directory. (The relationships contained
in the Directory supplement the relationships contained in the database.)
- Define criteria for the rows to be extracted by
specifying:
- Selection criteria for any selected table using
SQL syntax.
- A selection of rows chosen while browsing the data
(Point and Shoot).
- A sampling of rows, accomplished by extracting every nth
row.
- A maximum number of rows for a single table.
- A maximum number of children per parent.
- Grouping (e.g., extract 20 customers from each of
the 50 states).
- Ensure that the desired data is extracted using
the Show Steps function to review how Move will traverse the database.
Extract Process Report
An Extract Process Report is generated as part of the
Extract Process. The report contains general information and statistics
about the process. The content of the report reflects what has been
extracted─data, object definitions, or both.