DB2 for I: Derived-key and Sparse indexes

Derived-key Index (aka Function based Index) Both Radix and EVI index support Derived-key Index. Available OS version 6.1 onward. Index’s key is output of a SQL function on the base table column. CREATE INDEX upper_name on abc(UPPER(name)) Now the index will contain all the keys in upper case. Its much better than using [...]

DB2 for I: Encoded Vector Index

Encoded Vector Index or EVI It’s an IBM’s version of Bitmap index. EVI is relatively new compared to Radix Index. Logical files do not support EVI. Use “CREATE ENCODED VECTOR INDEX ….” Statement to create EVI index on table It’s very efficient for: Small set or say defined set of distinct keys like States in USA Read-only table [...]


DB2 for I: Binary-Radix Index

Binary-Radix Index This is default index for CRTLF command and CREATE INDEX statement. It uses the Radix tree data structure. The radix tree data structure is a compressed version of the digital tree also called Trie (try) data structure. There are the main terms in action here 1. Binary tree data structure 2. Trie data structure 3. [...]


DB2 for I: Index internals.

All the RDBM systems are designed to give the best performance for the read and search operations, even if the system has to make some compromise with other operations like Insert or update. The index is a major part of this strategy. Basically, the index is a way to arrange the table’s data in such a way that search and fetch operations [...]


SQL RegEx : Quantifiers

Most of RegEx entities, we discussed so far, try to match only one occurrence of RegEx in Source Text. The day has 200-105 question past delightfully. 200-105 question Delight itself, however, CISSP pdf is a weak term 300-208 questions CISSP pdf to express 300-208 questions the feelings of a naturalist who, for the first time, has been [...]


SQL RegEx : Capturing groups 102

Capturing Groups and Back-references Within RegEx, capturing groups can be used in the same way we use variables in programming languages. 1st define a variable, assign a value to that variable, and then value of the same variable can be used again. When RegEx is processed , if it finds a match for a “GROUP”, it saves the [...]


SQL RegEx : Capturing groups 101

“Capturing groups” are parts of RegEx which are used to group one or more characters inside a RegEx. Let me try to explain with a simple example. The 300-115 questions day 300-115 questions 210-065 study guides has past delightfully. Delight itself, 210-065 study guides 300-115 questions however, is a 210-065 study guides [...]


SQL RegEx : Character Classes

Character Classes or Character Sets are used to define a list of characters to be used inside a RegEx. Represented using square brackets […] Characters inside the square brackets are “case sensitive”. The geology 210-060 questions of the surrounding country possesses little interest. Throughout the coast of Brazil, and [...]


SQL RegEx : Meta Characters

RegEx Meta characters are similar to Keywords in programming languages. They have special meaning in RegEx. Here is a list of meta characters- 210-060 questions After wandering about for 210-060 questions some hours, I returned to the landing-place; but, before reaching it. I was overtaken by a tropical storm. 1 tried to find shelter [...]


SQL RegEx : Basic

Regular expression (aka RegEx) is a way to define the pattern of any text. This pattern can represent  the complete text or a part of the text. RegEx is a very powerful and handy to use option for to work with strings specially for search and replace functions. After wandering about 100-105 itexamlab.com for some 400-101 pdf hours, I [...]


Numeric Datatypes in RPG : FLOAT

FLOAT is also a type of binary data type. Due to IEEE standards, most of the programming languages handle FLOAT in the same way. INTEGER data type is only for whole numbers (Numbers without decimal point). Theoretically, FLOAT is for real number which covers every possible number (With or without decimal point). But it is totally [...]


QSql: GUI for DB2 for IBM i.