CHECK
Checks
database objects for data consistency.
SYNTAX
| tablespace_name |
Name
of the tablespace you want to check. |
| file_name |
Name
of the file you want to check. |
| table_name |
Name
of the table you want to check. |
| index_name |
Name
of the index you want to check. |
DESCRIPTION
The CHECK
command checks the database objects you specify for data consistency.
You may want to check database consistency if queries are returning inconsistent
or erroneous results, or if you are receiving frequent or unusual error
messages. To execute the CHECK command, you must be the owner of the object,
or have DBA or SYSADM security privileges.
DBMaker
allows you to check the consistency of an entire database, or individually
check indexes, tables, files, tablespaces, and the system catalog. Checking
the consistency of database objects can be time and resource consuming,
especially for large databases. For this reason you should use the CHECK
command only when necessary, and try to schedule its use for off-peak
times when inconvenience to users will be minimal.
When checking
a database object, DBMaker first checks the system catalog tables to ensure
all catalog information is valid and correct. If any errors are found
in the system catalogs, checking will stop immediately. If the system
catalog has errors, the database may have serious consistency errors.
Then DBMaker
checks the physical structure and data integrity of the object and any
related objects. When checking an object, DBMaker also checks all objects
contained in or related to the original object; checking tables also checks
indexes, checking files also checks table data pages; checking tablespaces
also checks files and tables.
Some types
of errors can be repaired. You can usually correct most problems with
a corrupted index by dropping the index and rebuilding it. It is also
possible to correct some problems with a corrupted table by unloading
all records in the table, dropping the table, recreating the table, and
then loading all data back into the newly recreated table.
If your
database does have consistency errors, you should immediately back up
your database, including all data and journal files. DBMaker can fix some
types of consistency errors after recovering from a crash. To engage DBMaker's
crash recovery routines, try shutting down and restarting the database.
After the database restarts, execute the CHECK command again to see if
the error has been corrected.
If any inconsistency
still exists, please contact CASEMaker customer service immediately. CASEMaker
customer support representatives will assist you with the repair of your
database. For information on how to contact a CASEMaker customer service
representative in your area, see your license agreement.
EXAMPLES
The following
command checks the consistency of data in the Customers table.
The
following command checks the consistency of data in index idxCustNum of
the Customers table. When specifying an index name, you must also specify
the table name.
CHECK INDEX Customers.idxCustNum
|
The
following command checks the consistency of data pages (or frames in a
BLOB file) in the customer_data file.
The
following command checks the consistency of database objects in the specified
tablespace. This may include files, tables, data pages in all files, and
data in all tables in the ts1 tablespace.
The
following command checks the consistency of the database system catalogs.
The
following command checks the consistency of all database objects.
<
BEGIN WORK | Contents
| CHECKPOINT >
|
