DBC - Databank Check
DBC investigates databank files to ensure that the physical structure is not damaged.
The overall syntax for the DBC program is:dbc [--all] [--extended] [databank_filename [result_filename [sysdb_filename]]]
extendedis specified, the contents of each row is checked to verify that each column value conforms to the rules for the column data type. SYSDB must be present to do this type of checking.
If a databank file is not closed, the contents of large objects are by default not checked. The reason is that TRANSDB may contain large object updates which affects the databank state.When
--allis specified, large objects are checked anyway. The utility can in these cases report errors that will correct themselves after restart of the system. It is therefore recomended to avoid this option.
File name for the databank to check. Sequential file created by DBC that contains the result of the verification. Filename for SYSDB used by the databank to check. This filename is required if any tables are using collations. If not specified the correct sort order for such tables is unknown.
If the filenames are not specified on the command-line, the program prompts for the name of the databank file, a name for the result file and the name of the system databank (SYSDB) file.
If an error occurs when opening the databank file (e.g. file not found or file locked by another user), or while creating the result file, an appropriate error message is displayed.
If the SYSDB filename is not specified and it is found that tables in the databank use collations, these tables are not verified and a warning message is displayed.
If no errors are detected in the databank file, the following message is shown:No errors found
The result file then contains statistics describing the physical databank organization. Otherwise, error descriptions (see below) are written to the result file, and the following message is displayed:* Errors logged in result file
The result file should be examined to investigate the nature of the errors, see Database Consistency.
It should be noted that the DBC program returns an error status (or warning) to the operating system when an error (or warning) is encountered. This may be useful when running it from scripts or in batch mode.
DBCreturns a status code to the environment executing the command. The status code can be examined by scripts.
VMS: On OpenVMS, the status codes correspond to the OpenVMS condition code severity levels.Use the
$SEVERITYsymbol in DCL command procedures.
The following return codes are used:
This code is used when the
DBCcommand has executed all options with no problems.
The DBC program operates directly against the databank file, with no reference to the Mimer SQL database server. The program may not be run on a file which is currently held open (an error message is displayed in such a case). The system administrator should arrange for exclusive access to the databank file during DBC operations.
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