Add the description of th workshop

Author: neodevelop

README.md

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 # Welcome to Database Refactor Workshop
+
+This workshop is intended to show one more practice for CI and CD, so, this is the chance for learning a new tecnhique for new and legacy systems with a relational database.
+
+## Requeriments
+
+- JDK 1.8+
+- MySQL 5.5+
+- A text editor
+
+Simple!!! Right!!!
+
+## Optional requirements
+
+- Git for your convenience and control
+- Groovy for an optimization
+- Gradle 5.x+ for final integration with your systems
+
+## Environment setup
+
+- Download **liquibase** from the [website](https://www.liquibase.org/download).
+- Add to your **PATH**, wherever you want Güin2, Linux, Mac, but only in the terminal
+- Verify your installation:
+
+```shell
+_> liquibase --version
+Starting Liquibase at vie, 12 jun 2020 20:12:54 CDT (version 3.10.0 #10 built at Thu Jun 11 09:47:49 UTC 2020)
+Liquibase Version: 3.10.0
+Liquibase Community 3.10.0 by Datical
+Running Java under /Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home/jre (Version 1.8.0_181)
+```
+
+## Database setup
+
+Well, it's easy:
+
+- Create a database `makingdevs_demo_db`
+
+```shell
+ mysql -u makingdevs -pmakingdevs -h 0.0.0.0 makingdevs_demo_db < create-schema-mysql.sql
+```
+
+## Exercises in this workshop
+
+1. So we're going to rename a table
+  * Rename the `inv` table to `invoice`
+  * Rename the `lineitem` table to `line\_item`
+  * Rename the `lidetail` table to `line\_item\_detail`
+1. Rename some columns in the `invoice` table
+  * Rename `invid` to `id`
+  * Rename `invnumber` to `invoice\_number`
+  * Rename `datetimecreated` to `date\_created`
+1. We're going to combine two columns using data transformation
+  * `invoice.udtime` and `invoice.uddate` should be combined into `invoice.date\_updated`
+  * First populate the `date\_created` new column with an `UPDATE` query that merges the `udtime` and `uddate` values
+    * HINT: `udtime` + `uddate`
+  * What do you think about this refactoring?
+    * drop or kept them?
+1. Create tables
+  * `contact\_ball\_of\_mud` is too ambitious of a table (or insufficiently coherent). Let's begin splitting it up.
+    * The **contact** table should contain name fields, gender, email address, street address, birthday, occupation, and national ID
+    * The **security\_info** table should contain password and mother's maiden name
+    * The **credit\_card** table should contain credit card type, number, expiration and CVV
+    * Choice of data type for each column is left as an exercise for the student.
+  * Don't run this refactoring yet!
+1. Tagging and rolling back
+  * Tag the database, then run the table rename refactoring written in the previous step
+  * Now roll back to continue development on the refactoring
+1. Finish refactoring of `contact\_ball\_of\_mud`
+  * Write data transformation code to populate the three tables from their source
+  * Remember that `security\_info` and `credit\_card` should have foreign keys to contact. Be sure to add these constraints with the appropriate refactorings
+1. Add a column
+  * Add a `full\_name` column to contact
+  * Write data transformation SQL to populate it with the three existing name fields combined
+    * HINT: `CONCAT_WS()`
+  * Don't drop of the source name columns.
+1. Create a trigger
+  * Create a file called __contact\_insert.sql__
+    * Write trigger logic to keep `full\_name` up to date with the fields for first name, middle initial, and last name every time a new record is inserted
+  * Create a file called *contact\_update.sql*
+    * Same logic as the insert trigger
+  * Write changeSets that use the sqlFile refactoring to install these triggers.
+    * Remember the runOnChange attribute.
+    * HINT: be sure the changeSet is idempotent!
+1. Use **gradle**, this is the thing that you should to do...
+  * Restart the steps but now with gradle
+  * Use the Groovy DSL for the new migrations
+1. Introduce surrogate key
+  * Add an auto\-incrementing column to line\_item called id.
+  * Add a primary key constraint on id.