The mi_collection_open_with_options() function
The mi_collection_open_with_options() function opens a collection in a specified open mode.
Syntax
MI_COLL_DESC *mi_collection_open(conn, coll_ptr, control)
MI_CONNECTION *conn;
MI_COLLECTION *coll_ptr;
mi_integer control;- conn
- A pointer to a connection descriptor established by a previous call to mi_open(), mi_server_connect(), or mi_server_reconnect().
- coll_ptr
- A pointer to the collection structure to open.
- control
- A bit-mask integer value that specifies the type of collection
cursor to create and open. The following bit-mask flags are valid:
- MI_COLL_READONLY
- Cursor is read-only.
- MI_COLL_NOSCROLL
- Cursor A sequential cursor (not a scroll cursor).
Valid in client LIBMI application? Valid in user-defined routine? Yes Yes
Usage
The mi_collection_open_with_options() function is a constructor function for the collection descriptor. The function opens the collection that coll_ptr references and returns a collection descriptor for the open collection. Other DataBlade® API collection functions use this collection descriptor to access the elements of a collection.
For a description of collections, see the HCL OneDB™ DataBlade API Programmer's Guide.
Server only: The mi_collection_open_with_options() function
allocates a new collection descriptor in the current memory duration.
This
function creates a collection cursor to hold the collection elements.
By default, this cursor is an update scroll cursor. If this type of
cursor is not adequate for your DataBlade
API module,
you can create a collection cursor with characteristics specified
by a bit mask in the control argument.
- Collection cursor type
- Control-flag value
- Update scroll cursor
- None (default)
- Read-only scroll cursor
- MI_COLL_READONLY
- Update sequential cursor
- MI_COLL_NOSCROLL
- Read-only sequential cursor
- MI_COLL_READONLY + MI_COLL_NOSCROLL
This function is useful for accessing collection subqueries.
Return values
- An MI_COLL_DESC pointer
- The address of the collection descriptor for the opened collection.
- NULL
- The function was not successful.