The following -REGION qualifiers can be used with the ADD, CHANGE, or TEMPLATE commands.
-C[OLLATION_SEQUENCE]=id number
Specifies the number of the collation sequence definition to be used as the default for this database file. The number can be any integer from 0 to 255. The number you assign as a value must match the number of a defined collation sequence that resides in the shared library pointed to by the environment variable gtm_collate_n. For information on defining this environment variable and creating an alternate collation sequence, refer to the "Internationalization" chapter in the GT.M Programmer's Guide.
The minimum COLLATION_SEQUENCE ID number is zero, which is the standard M collation sequence.
The maximum COLLATION_SEQUENCE ID number is 255.
By default, GDE uses zero (0) as the COLLATION_SEQUENCE ID.
-D[YNAMIC_SEGMENT]=segment-name
Specifies the name of the segment to which the region is mapped. Segment-names are not case-sensitive, but are displayed as uppercase by GDE.
The minimum length is one alphabetic character.
The maximum length is 16 alphanumeric characters.
Specifies the maximum size of keys, in bytes, which can be stored in the region. The KEY_SIZE must be less than the RECORD_SIZE. GDE rejects the command if the KEY_SIZE is inappropriate for the RECORD_SIZE.
The minimum KEY_SIZE is three bytes.
The maximum KEY_SIZE is 255 bytes.
When determining the maximum key size, applications should consider the following:
GT.M uses packed decimal representation for numeric subscripts which may be larger or smaller than the original representation.
GT.M substitutes an element terminator for the caret (^), any comma (,), and any right parenthesis ()).
GT.M adds an extra byte for every string element, including the global name.
For example, the key ^ACN ("Name", "Type") internally occupies 17 bytes.
By default, GDE uses a KEY_SIZE of 64 bytes.
Specifies the maximum RECORD_SIZE, in bytes, which can be stored in the region. The KEY_SIZE must be less than the RECORD_SIZE. GDE rejects the command if the KEY_SIZE is inappropriate for the RECORD_SIZE.
If the RECORD_SIZE is greater than the BLOCK_SIZE minus the number of reserved bytes, minus the size of the record header (7 or 8 bytes, depending on your platform), GDE issues an error message.
The minimum RECORD_SIZE is seven or eight, depending on your platform.
The maximum record size (in bytes) is:
block_size - block_header_size - reserved_bytes
where block_header_size is 16 bytes.
By default, GDE uses a RECORD_SIZE of 256 bytes.
Indicates whether GT.M allows null subscripts for global variables stored in the region (i.e., whether GT.M permits references such as ^aaa("",1)).
By default, regions have -NONULL_SUBSCRIPTS.
-[NO]J[OURNAL][=journal-option-list]
Specifies whether the database file allows journaling. If it does, this qualifier establishes characteristics for the journal file.
-NOJOURNAL specifies that updates to the database file are not journaled. -NOJOURNAL does not accept an argument assignment.
-JOURNAL specifies that journaling is allowed. -JOURNAL takes one or more arguments in a journal-option-list. The journal-option-list contains keywords separated with commas (,) enclosed in parentheses ( ). If the list contains only one keyword, the parentheses are optional.
Although you do not have to establish the criteria for your journaling process at this point, it is efficient to do so, even if you are not entirely sure you will use journaling. The options available for -JOURNAL set up the environment, so it is ready for you to enable with MUPIP SET -JOURNAL. You can also change or add any of the established options at that time.
For more information about journaling, see Chapter 6: “GT.M Journaling”.
The journal-option-list includes:
The following section describes some -JOURNAL options.
[NO]BEFORE_IMAGE controls whether the journal should capture before images of information that an update is about to modify.
The BEFORE_IMAGE option is required if you plan to consider "roll-back" (Backward) recovery of the associated database file or if you plan to use certain database replication options. For a description of this type of recovery, see Chapter 6: “GT.M Journaling”.
Specifies the name of the journal file.
The name should always be enclosed in quotation marks in this context.
Journal file-specifications-names are limited to 255 characters.
By default, GDE derives the file-specification-name from the database "file-name".
By default, GDE uses a journal file extension of .mjl.