The am_create purpose function
The database server calls am_create to process a CREATE INDEX statement. The am_create function creates the index, based on the information in the table descriptor, which describes the keys in an index.
Syntax
mi_integer am_create(MI_AM_TABLE_DESC *tableDesc)- tableDesc
- Points to the index descriptor.
Usage
Even if the access method does not provide an am_create function, the database server automatically adds the created object to the system catalog tables, such as systables or sysindices. For example, a user might issue the CREATE TABLE command to register an existing index in another database of the same database server instance.
The am_create function
typically:
- Calls accessor functions to extract table specifications from the table descriptor, including a pointer to the row descriptor
- Calls DataBlade API functions to extract column attributes from the row descriptor
- Verifies that the access method can provide all the requirements that the CREATE INDEX specifies
- Validates CREATE INDEX statements that specify identical keys
- Calls the appropriate DataBlade API functions to create a smart large object or interact with the operating system for file creation, as described in Manage storage spaces
- Executes support functions that build the index
The access method might supply the support functions or execute UDRs from outside the access-method shared-object library.
Important: By default, transaction logging is disabled
in sbspaces. To find out how to turn logging on, see Ensure data integrity.
Return values
- MI_OK
- Indicates success.
- MI_ERROR
- Indicates failure.
Related topics
In the HCL
Informix®
DataBlade API Programmer's Guide, see
the descriptions of:
- DataBlade API functions, such as mi_lo_create(), and create-time constants
- DataBlade API accessor functions for the row descriptor