Updating a clob Free dating sexcams and photos without paying a dime or signing in with no membership
This is where the (notionally invisible and you don’t need to know about it) LOBINDEX comes into play.
Oracle maintains an index keyed by (LOB_ID, chunk_number) *** pointing to all the chunks of a LOB in order, so when you update a single chunk Oracle simply creates an updated copy of the chunk and changes the appropriate index entry to point to the new chunk.
So here’s the clever bit – how big will the LOBSEGMENT grow when I update that one CLOB ?
To UPDATE a BLOB/CLOB with a string, the string must be cast to RAW.The file handler is “EXAMPLE_LOB_DIR” and the directory is “/directory/to/filter.xml”. Update Column In Database Now that we have the file handler, we’ll use the chunk of SQL Syntax below, to read the XML File into a SQL UPDATE statement, which updates DATA(column) in the CONFIG(table) with data in the dest_clob(xml file).DECLARE dest_clob CLOB; src_clob BFILE := BFILENAME(‘EXAMPLE_LOB_DIR’, ‘filter.xml’); dst_offset number := 1 ; src_offset number := 1 ; lang_ctx number := DBMS_LOB.The index is actually quite an odd one because it serves two functions; apart from pointing to current lobs by chunk number, it also points to “previous” chunks by timestamp (specifically the number of seconds between Midnight of 1st Jan 1970 and the time at which the chunk was “overwritten”).This makes it easy for Oracle to deal with the retention interval for LOBs – any time it needs space in the LOBSEGMENT it need only find the minimum timestamp value in the index and compare it with to see if there are any chunks available for re-use.