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How to Decode TLV Quickly

In TLV, the format is Tag, Length, and Value. The TLV protocol needs this type of data. Here you will know how to decode TLV data. According to IBM , TLV data is three parts. The tag tells what type of data it is. The length field denotes the length of the value. The Value-field denotes the actual value. Structure of TLV. TLV comprises three field values.  Tag Length Value EMV formulated different tags. They have their meanings. Usually, the Tag and Length together takes 1 to 4 bytes. The Best example for TLV. In the below example, you can find the sample TAG, LENGTH, and VALUE fields. [Tag][Value Length][Value] (ex. " 9F4005F000F0A001 ") where Tag Name =  9F40 Value Length (in bytes) =  05  Value (Hex representation of bytes. Example, "F0" – 1-byte) =  F000F0A001 In the above message, tag 9F40 has some meaning designed by EMV company. Here  you can find a list of EMV Tags. How to read the TLV Tag: 1 or 2 bytes Length: Length of the Value. F0-00-F0-A0-01 ==> 5 By

Oracle 12C 'Bitmap Index' benefits over B-tree Index

Oracle 12C 'Bitmap Index' benefits over B-tree Index
#Oracle 12C 'Bitmap Index' benefits over B-tree Index:
A bitmap index has a significantly different structure from a B-tree index in the leaf node of the index. It stores one string of bits for each possible value (the cardinality) of the column being indexed.

Note: One string of BITs means -Each tupple of possible value it assigns '1' bit in a string.So, all the BITs become a string ( This is an example, on which column you created BIT map index)

The length of the string of bits is the same as the number of rows in the table being indexed.

In addition to saving a tremendous amount of space compared to traditional indexes, a bitmap index can provide dramatic improvements in response time because Oracle can quickly remove potential rows from a query containing multiple WHERE clauses long before the table itself needs to be accessed.

Multiple bitmaps can use logical AND and OR operations to determine which rows to access from the table.

Although you can use a bitmap index on any column in a table, it is most efficient when the column being indexed has a low cardinality, or number of distinct values.

For example, the GENDER column in the PERS table will be either NULL, M, or F. The bitmap index on the GENDER column will have only three bitmaps stored in the index. On the other hand, a bitmap index on the LAST_NAME column will have close to the same number of bitmap strings as rows in the table itself. The queries looking for a particular last name will most likely take less time if a full table scan is performed instead of using an index. In this case, a traditional B-tree non-unique index makes more sense.

A variation of bitmap indexes called bitmap join indexes creates a bitmap index on a table column that is frequently joined with one or more other tables on the same column. This provides tremendous benefits in a data warehouse environment where a bitmap join index is created on a fact table and one or more dimension tables, essentially pre-joining those tables and saving CPU and I/O resources when an actual join is performed.

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