To access an existing smart large object in the database, you need to perform the following steps. For details on a step, see the page listed under "More Information."
| Step | Task | Smart-Large-Object Function | More
Information |
|---|---|---|---|
| 1. | Execute a SELECT statement to obtain the LO handle of the smart large object from the CLOB or BLOB column. | mi_exec( ),
mi_exec_prepared_statement( ), mi_value( ) |
page Selecting the LO Handle |
| 2. | Convert the returned column value into an LO handle. | C Cast | page Converting an LO Handle Between Binary and Text |
| 3. | Open the smart large object that the LO handle identifies and return a valid LO file descriptor. | mi_lo_open( ) | page Opening a Smart Large Object |
| 4. | Read a specified number of bytes and store them in a user-defined buffer. | mi_lo_read( ),
mi_lo_readwithseek( ) |
page Reading Data from a Smart Large Object |
| 5. | Close the smart large object. | mi_lo_close( ) | page Freeing a Smart Large Object |
| 6. | Free resources. | mi_lo_release( ) | page Freeing Resources |
Figure 29 shows the first four of these steps that a DataBlade API module uses to access the smart-large-object data from the emp_picture column of the employee table (Figure 26).