Long and Long Raw Columns

See Also

Putting

Long and long raw columns of an Oracle database can contain up to 2 gigabytes of data. Data of less than 64K bytes can be put into the database using simple assignment, but data exceeding 64K bytes must be put into the database using AppendChunk. The Oracle database libraries do not allow putting of data in multiple pieces, so the data is held internally and put in one piece upon an Update.

Fetching

Long and long raw columns of an Oracle database can contain up to 2 gigabytes of data. This makes it impractical to retrieve all data from a long or long raw column automatically when it is selected. Instead, the first 64K bytes is retrieved and the Oracle ROWID is cached locally so that the row containing the long or long raw column can be located and then retrieved when using the GetChunk method. If the Oracle ROWIDs cannot be obtained on a query with a long or long raw column, then the long or long raw column will not be accessible and an error will be generated if field access is attempted.

Editing

Before an Edit can be started, a column's locally cached value is compared with its current database value. If the values match, the edit proceeds; otherwise an error is generated. Since long and long raw columns may contain up to 2 gigabytes of data, no comparison is done before an Edit is started.