# Flyway Overview

**Flyway is a version control tool for database versioning**

### [Official documentation](https://flywaydb.org/documentation/)

**Cheatsheet:**

| Command  | What it does                                                                                 |
| -------- | -------------------------------------------------------------------------------------------- |
| migrate  | Migrates the database                                                                        |
| clean    | Drops all objects in the configured schemas                                                  |
| info     | Prints the details and status information about all the migrations                           |
| validate | Validates the applied migrations against the ones available on the classpath                 |
| undo     | Undoes the most recently applied versioned migrations                                        |
| baseline | Baselines an existing database, excluding all migrations up to and including baselineVersion |
| repair   | Repairs the schema history table                                                             |

**For Debug use flax `-x`**

* a prefix: which defaults to V
* a version: dots or underscores separated in as many parts as one likes
* separator: which defaults to \_\_ (two underscores) and separates the version from the description
* description: a text with words separated by underscores or spaces
* suffix: which defaults to .sql

**In Flyway home**

* Initial script called `flyway` which accepts parameters
* `conf` folder where you can find the configs for different schemas Example:

```bash
flyway.url=jdbc:oracle:thin:@//<servername>:<port>/<service_name>
flyway.user=<user_name>
flyway.password=${FLYWAY_PASSWORD}
flyway.schemas=<Schema_name>
flyway.cleanOnValidationError=false
flyway.cleanDisabled=true
flyway.locations=filesystem:<script_foder_location>
```

* Home file structure:&#x20;

**Script for case migration for different schemas:**

```bash
#!/bin/bash
# Static variables
xml_home='<path_to_tomcat_xml>'
# Flyway variables
export JAVA_HOME=/appl/tomcat/java/jdk-11.0.9
path_to_flyway=/home/load/flyway-5.1.4
flyway_option=$1
db_schema=$2
#############################################################################
if [ $# != 2 ]; then
   echo "You must pass exactly 2 parameters to flyway. Example: run_flyway.sh migrate gui"
   exit 0
fi
#############################################################################
# FUNCTIONS:
function get_data_from_xml() {
    # Defining required variables
    FLYWAY_PASSWORD=$(cat ${xml_home} | grep -oP '(?<=password=").*?(?=")' | sed 's/\&quot\;/\"/' | head -${number_required} | tail -1)
}
function export_variables() {
    echo "Exporting required variables"
    export FLYWAY_PASSWORD
}
function execute_flyway() {
    echo  "Executing ${path_to_flyway}/flyway -configFiles=${path_to_flyway}/conf/${conf_home} ${flyway_option}"
    ${path_to_flyway}/flyway -configFiles=${path_to_flyway}/conf/${conf_home} ${flyway_option}
}
function flyway_centralized() {
    get_data_from_xml
    export_variables
    execute_flyway
}
function adm_func() {
    conf_home="adm.conf"
    number_required="1"
    flyway_centralized
}
function input_func() {
    conf_home="input.conf"
    number_required="2"
    flyway_centralized
}
function storage_func() {
    conf_home="storage.conf"
    number_required="3"
    flyway_centralized
}
function history_func() {
    conf_home="history.conf"
    number_required="4"
    flyway_centralized
}
function  gui_func() {
    conf_home="gui.conf"
    number_required="5"
    flyway_centralized
}
function output_func() {
    conf_home="output.conf"
    number_required="6"
    flyway_centralized
}
case $db_schema in
    # CASE ALL:
    all)
    adm_func
    input_func
    storage_func
    history_func
    gui_func
    ;;
    # CASE ADM:
    adm)
    adm_func
    ;;
    # CASE INPUT
    input)
    input_func
    ;;
    # CASE STORAGE
    storage)
    storage_func
    ;;
    # CASE HISTORY
    history)
    history_func
    ;;
    # CASE GUI
    gui)
    gui_func
    ;;
    # CASE OUTPUT
    output)
    output_func
    ;;
    # ERROR HANDLING
    *)
    echo "Incorrect keyword. Should be: all, adm, input, storage, history, gui or output."
    ;;
  esac
##done
echo "database migration done"
```