This is a brief look at the directory structure of how you can arrange intialisation and configuration files for your databases. Here we only look at "selfmanaged" but it works the same for "dbaas" deployments as well where you need custom configuration or intitialisation for your use case.

${HOME}/providerscripts/database/selfmanaged/postgres/live:  
total 4  
-rw-r--r-- 1 root root 227 May 21 22:19 postgres.psql ( you can write any intialisation you want for your datbase here in psql )

${HOME}/providerscripts/database/selfmanaged/postgres/inactive: (you can store currently inactive psql scripts here and copy them to 'live' when you want to use them)  
total 8  
-rw-r--r-- 1 root root 283 May 21 22:19 with-superuser.psql  
-rw-r--r-- 1 root root 227 May 21 22:19 without-superuser.psql

${HOME}/providerscripts/database/selfmanaged/mysql/live:  
total 8  
-rw-r--r-- 1 root root 1071 May 21 22:19 mysql.sql  ( you can write any intialisation you want for your datbase here in sql )  
-rw-r--r-- 1 root root  731 May 21 22:19 mysql.config (you can configure mysql anyway you want using this file )

${HOME}/providerscripts/database/selfmanaged/mysql/inactive:  
total 12  
-rw-r--r-- 1 root root 1160 May 21 22:19 root-enabled.sql   (you can store currently inactive mysql scripts here and copy them to 'live' when you want to use them)  
-rw-r--r-- 1 root root 1071 May 21 22:19 root-disabled.sql  
-rw-r--r-- 1 root root  731 May 21 22:19 mysql.config.default

${HOME}/providerscripts/database/selfmanaged/mariadb/live:  
total 8   
-rw-r--r-- 1 root root 1078 May 21 22:19 mariadb.sql     ( you can write any intialisation you want for your datbase here in sql )  
-rw-r--r-- 1 root root  770 May 21 22:19 mariadb.config  (you can configure mariadb anyway you want using this file )

${HOME}/providerscripts/database/selfmanaged/mariadb/inactive:  
total 12  
-rw-r--r-- 1 root root 1139 May 21 22:19 root-enabled.sql (you can store currently inactive mariadb scripts here and copy them to 'live' when you want to use them)  
-rw-r--r-- 1 root root 1077 May 21 22:19 root-disabled.sql  
-rw-r--r-- 1 root root  701 May 21 22:19 mariadb.config.default