Showing posts with the label mainframe cloud computing

Featured Post

SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

The Story behind Mainframe to Cloud Real Journey

Mainframe to CLOUD: Mainframe computing took off in the 1950s and gained much prominence throughout the 1960s. Corporations such as IBM (International Business Machines), Univac, DEC (Digital Equipment Corporation), and Control Data Corporation started developing powerful mainframe systems. These mainframe systems mainly carried out number-crunching for scientists and engineers. The main programming language used was Fortran. Then in the 1960s, the notion of database systems was conceived and corporations developed database systems based on the network and hierarchical data models. The database applications at that time were written mainly in COBOL. Cloud Vs Mainframe In the 1970s, corporations such as DEC created the notion of mini-computers. An example is DEC's VAX machine. These machines were much smaller than the mainframe systems. Around that time, terminals were developed. This way, programmers did not have to go to computing centers and use punch cards