OmniAccess API

Managing Large Lists of Rows

oaassignvalues provides the mechanism to pass any number of search values in repeated executions of an oafetch loop. This mechanism can be used to effectively break down one oversized array of search values into several smaller, manageable arrays. oafetch can also be incorporated into the loop to support forward and backward reads through a list of qualified rows.

The data parameter of oaassignvalues contains the actual data to pass to the $VALUES buffer. Each value contained in data is assumed to be of the defined type and length of the column on the left side of the $VALUES expression in oaselect’s criteria parameter. For example, if the criteria parameter contains the expression CUSTOMER_NO IN $VALUES, and CUSTOMER_NO is defined as TYPE INTEGER LENGTH 2 in the environment catalog, oaselect assumes that the values in the data parameter of oaassignvalues are also TYPE INTEGER LENGTH 2 (two-byte signed integers).

The num_values parameter tells oaassignvalues how many elements (values) data contains. Based on this information, as well as the number provided in the oaselect $VALUES declaration, oafetch can use the criteria to retrieve rows.

The labels parameter tells oaassignvalues which $VALUES token to use if there are several $VALUES tokens on the oaselect criteria expression. When using more than one $VALUES token in a call to oaselect, a different $VALUES label must first be assigned for each $VALUES token. oaassignvalues must be called once for each $VALUES token in the oaselect expression before calling oafetch.

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