- MySQL Event
MySQL Events or scheduled events are tasks that execute according to a specified schedule. They are stored in the database and executed at one or more intervals. For example, you can create an event that optimizes a table by backfilling data from another table the database that runs at 1:00 AM…
- MySQL Index
An index is a data structure such as B-Tree that improves the speed of data retrieval on a table at the cost of additional writes and storage to maintain it. Indexes are a type of lookup table that is used to improve the performance of SELECT queries. Without an index, MySQL performs lookups by…
- Linux prepend content to a file
Prepend content to a file Use sed with -i option. You can also specify the line to which the content will prepend to. sed -i ” ‘1s/^/package home;/” Home.java Prepend content to multiple files Here I need to add a package to 200 java files. To do this manual would be tedios. for f […]
- CSS Margin
margin properties are used to create space around elements, outside of any defined borders. margin: top right bottom left; margin: 10px 15px 20px 25px; top – 10px right – 15px bottom – 20px left – 25px margin: top right/left bottom; margin: 10px 20px 25px; top – 10px right/left – 20px bottom – 25px…
- Elasticsearch – Mappings, and Why You Should Write Your Own
Dynamic mapping guesses a field's type from the first document it sees, and it guesses from ONE document. A price that happens to arrive as 120 becomes a long and the next listing at 119.50 is a problem. Writing an explicit mapping, what dynamic: strict buys, multi-fields, and the constraint that shapes everything afterwards: a field's type cannot be changed once it has been written.