Application Express User's Guide > Advanced Programming Techni... > Using Collections > Determining Collection Status
Determining Collection Status |
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The p_generate_md5 parameter determines if the MD5 message digests are computed for each member of a collection. The collection status flag is set to FALSE immediately after you create a collection. If any operations are performed on the collection (such as add, update, truncate, and so on), this flag is set to TRUE.
You can reset this flag manually by calling RESET_COLLECTION_CHANGED, for example:
HTMLDB_COLLECTION.RESET_COLLECTION_CHANGED ( p_collection_name => collection name)
Once this flag has been reset, you can determine if a collection has changed by calling COLLECTION_HAS_CHANGED, for example:
l_changed := HTMLDB_COLLECTION.COLLECTION_HAS_CHANGED( p_collection_name => collection_name);
When you add a new member to a collection, an MD5 message digest is computed against all 50 attributes and the CLOB attribute if the p_generated_md5 parameter is set to YES. You can access this value from the MD5_ORIGINAL column of the view HTMLDB_COLLECTION. You can access the MD5 message digest for the current value of a specified collection member by using the function GET_MEMBER_MD5. For example:
HTMLDB_COLLECTION.GET_MEMBER_MD5 ( p_collection_name => collection name, p_seq => member sequence number ); RETURN VARCHAR2;