| 1 | Hash name | Input | Char(10) |
| 2 | Physical file | Input | Char(10) |
| 3 | Physical file library | Input | Char(10) |
| 4 | Logical file | Input | Char(10) |
| 5 | Logical file library | Input | Char(10) |
| 6 | Expression | Input | Char(64) |
| 7 | Number-of-keys | Input | Binary(4) |
| 8 | Key ranges | Input | Char(*) |
The Create Database Hash (qdbcrtha) API sets up the environment to enable the Run Database Hash (qdbrunha) API for a physical file that has a uniquely keyed logical file built over it. The logical file may have up to five integer keys associated with it. It is called as a function call of the form 'xx = qdbcrtha(parameter-list)', where xx is a long integer and the parameter list is as defined here. The value of xx is set to a return code as defined in the Returned Value topic.
The hash name to be created. A unique name must be selected for each hash function that will be used on the system.
The name of the physical file that will be accessed using the hash.
The name of the library where the physical file resides.
The name of the logical file that will be used to build the hash. The logical file must be uniquely keyed.
The name of the library where the logical file resides.
A valid mathematical expression that uses all the key values of a uniquely keyed logical file to determine the hash value for a particular record. The special value of *DFT can be used to allow the API to create an expression based on expected cardinalities (number of expected unique values for each key) of the keys in the logical file. Possible values are:
The number of keys used in the logical file.
A two-value structure with up to five occurrences, containing the names of
the key fields followed by the expected cardinality of the key. For more
details, see Field Descriptions.
| Offset | Type | Field | |
|---|---|---|---|
| Dec | Hex | ||
| CHAR(10) | Name of key | ||
| BINARY(4) | Cardinality | ||
Name of key. The name of the key field that is used in the logical file, which is referenced in this API. The names are for documentation purposes only.
Cardinality. The number of sequential values expected to be
used for each key, respectively. The cardinality values are required if *DFT
has been specified for the value of the expression parameter.
The returned value contains a numeric indication as to what took place during the request to add a hash function. The possible values are:
Only the error conditions listed in the Returned Value are monitored. No error messages other than the value of the return code parameter are returned.