OmniAccess API

OAOPENCURSOR

oaopencursor establishes a working space or “cursor” that maintains the environment for all OmniAccess procedure calls that reference it.

A cursor defines the environment for qualifying, retrieving, updating and deleting rows. An example of information identified by the cursor includes the current pointer in a qualified subset after an oaqualify operation. Through the use of multiple cursors, it is possible to simultaneously read different qualified subsets for the same table. Cursor is passed as the first parameter of most of the OmniAccess routines.

Syntax

oaopencursor (instance, options, status, cursor)

instance -- Identifies the unique connection to a catalog established by calling oaconnect. Instance is a 32-bit signed integer passed by value.

options -- Is the type of access to be used by this cursor. Options is a character value passed by reference, with a maximum length of 256 bytes, including a semicolon or null terminator. The valid options values are:

status -- Returns information about the success or failure of the oaopencursor routine. A zero in status word 1 indicates a successful oaopencursor call. The status structure is passed by reference and contains fourteen 32-bit signed integers, followed by a 36-character buffer.

cursor -- Is a 32-bit signed integer passed by reference from oaopencursor. oaopencursor initializes cursorto an integer that identifies a working area of the environment for subsequent OmniAccess calls. If oaopencursor is not successful, cursor contains a zero.

top

Options

DA -- causes all OmniAccess calls for that cursor to affect only the underlying data files.

IA -- causes all OmniAccess calls for that cursor to affect only the OMNIDEX index files.

IABASEID -- returns the TurboIMAGE base ID to status.data5 to support subsequent calls to ImagePlus intrinsics in that cursor.

OPTIMIZATION -- sets the selection optimization for oaselects and oalists using this cursor. Optimizations are set through an equation:

OPTIMIZATION='ASKQUAL,ASKRETRIEVAL'

The data access optimization you choose for oaselect supersedes any optimization you may have chosen for the cursor when you opened it with oaopencursor.

REQUIRED_OPTIMIZATION -- The Required Optimization feature enforces specified optimization rules on a select statement. In the event that a select statement cannot be optimized according to those rules, the select will stop processing and return an error. Subsequent operations against that select such as fetches and exports, will be disallowed. Required optimizations are set through an equation:

REQUIRED_OPTIMIZATION='NO_MULTIFINDS,NO_UNOPTIMIZED_CRITERIA'

top

Example

top