TurboIMAGE/XL Database Management System Reference Manual (30391-90012)

72 Chapter3
Defining a Database
Set Part
item name is the name of a data item defined in the item part.
path count is an integer between 0 and 64, inclusive, which is used with the key item
only. It indicates the number of paths that will be established to various
detail data sets. Refer to chapter 2 for more information about paths. A
path count must be specified for one, and only one, item in the master set.
A zero path count can be used with a manual master data item to indicate
the key item. A manual master defined in this way is not linked to any
detail data set. An automatic master has one item that must have a path
count greater than zero.
maximum capacity is the maximum number of entries the data set can contain: that is,
the data set's capacity. It must be less than or equal to 2
31
−1
(2,147,483,647) and is limited by the size of the entry as well as the
maximum size of an MPE/iX file, jumbo or non-jumbo.
For non-jumbo data sets, if the capacity expansion parameter, initial
capacity, is specified and is less (not zero) than the maximum capacity, the
data set is enabled for dynamic expansion. Note that specifying initial
capacity for a jumbo data set will generate an error. When enabled for
dynamic expansion, the maximum capacity is adjusted by
TurboIMAGE/XL to represent an even multiple of the blocking factor.
Otherwise, it remains unchanged.
blocking factor is the number of data set media records in one block. If a value is not
specified, it is calculated by DBSCHEMA.
initial capacity is the initial capacity for the data set, that is, the number of entries for
which space will be allocated and initialized when the data set is created.
This number must be between 1 and 2
31
−1 inclusive but must be less than
or equal to the maximum capacity. Specifying initial capacity for a jumbo
data set will generate an error. This parameter should be used to closely
approximate the current volume of data. If it is very low, there can be
frequent expansions leading to severe disk fragmentation. Initial capacity
is an optional parameter. If initial capacity is not specified, or if initial
capacity is either zero or equal to the maximum capacity, then dynamic
capacity expansion is not enabled for the data set, and maximum capacity
is used for the data set file creation.
increment is either the number of entries or the percentage of the initial capacity by
which the data set will be expanded each time its initialized space is
exhausted. If a percentage is used, the percent sign (%) must follow the
incremental amount. This increment parameter can only be used if the
initial capacity parameter is also specified. This number must be 1 to
32767 inclusive for percent, or 1 to 2
31
−1 (2,147,483,647) inclusive for
number of entries. If it is very low, there can be frequent expansions
leading to severe disk fragmentation. If it is very high, DBPUT may take a
long time to complete which could impact other database users.
The number of entries defined, or the entries calculated from the percent,
cannot exceed the maximum entry count minus the initial allocation. The
increment is an optional parameter. If the increment is not specified for