Add Create Database Uses Template1 as a postgres til

README.md

@@ -9,7 +9,7 @@ and pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://tinyletter.com/jbranchaud).
 
-_933 TILs and counting..._
+_934 TILs and counting..._
 
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@@ -449,6 +449,7 @@ _933 TILs and counting..._
 - [Count The Number Of Trues In An Aggregate Query](postgres/count-the-number-of-trues-in-an-aggregate-query.md)
 - [Create A Composite Primary Key](postgres/create-a-composite-primary-key.md)
 - [Create An Index Without Locking The Table](postgres/create-an-index-without-locking-the-table.md)
+- [Create Database Uses Template1](postgres/create-database-uses-template1.md)
 - [Create hstore From Two Arrays](postgres/create-hstore-from-two-arrays.md)
 - [Create Table Adds A Data Type](postgres/create-table-adds-a-data-type.md)
 - [Creating Conditional Constraints](postgres/creating-conditional-constraints.md)

postgres/create-database-uses-template1.md

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+# Create Database Uses Template1
+
+Whenever you use the [`create
+database`](https://www.postgresql.org/docs/current/sql-createdatabase.html)
+query, unless otherwise specified, it will create it by cloning `template1` by
+default.
+
+You can view, inspect, and even modify this database template by connecting to
+it.
+
+```sql
+\c template1
+```
+
+Every Postgres cluster starts with two templates.
+
+```sql
+select datname from pg_database where datistemplate = true;
+  datname
+-----------
+ template1
+ template0
+(2 rows)
+```
+
+You cannot however connect to and modify `template0`. It is a fallback clone of
+`template1` that you can utilize if you ever modify `template1` and need to
+restore it.
+
+[source](https://supabase.io/blog/2020/07/09/postgresql-templates/)