PostgreSQL Tutorial

• PostgreSQL - Introduction
• Install PostgreSQL on Windows
• Install PostgreSQL on Mac
• PostgreSQL - Loading a Database
• PostgreSQL - Create Database
• PostgreSQL - ALTER DATABASE
• PostgreSQL - DROP DATABASE
• PostgreSQL - Rename Database
• PostgreSQL - Copy Database
• PostgreSQL - Size of a Database
• PostgreSQL - Show Databases

Data Types

• PostgreSQL - Data Types
• PostgreSQL - Boolean Data Type
• PostgreSQL - CHAR Data Type
• PostgreSQL - VARCHAR Data Type
• PostgreSQL - TEXT Data Type
• PostgreSQL - NUMERIC Data Type
• PostgreSQL - SMALLINT Integer Data Type
• PostgreSQL - INTEGER Data Type
• PostgreSQL - BIGINT Integer Data Type
• PostgreSQL - Date Data Type
• PostgreSQL - Timestamp Data Type
• PostgreSQL - UUID Data Type
• PostgreSQL - TIME Data Type
• PostgreSQL - Interval Data Type
• PostgreSQL - User-defined Data Type
• PostgreSQL - Array Data Type
• PostgreSQL - hstore Data Type
• PostgreSQL - JSON Data Type

Querying & Filtering Data

• PostgreSQL - SELECT
• PostgreSQL - SELECT DISTINCT clause
• PostgreSQL - ORDER BY clause
• PostgreSQL - WHERE clause
• PostgreSQL - LIMIT clause
• PostgreSQL - FETCH clause
• PostgreSQL - IN operator
• PostgreSQL - IS NULL operator
• PostgreSQL - LIKE operator
• PostgreSQL - NOT LIKE operator
• PostgreSQL - BETWEEN operator
• PostgreSQL - HAVING clause
• PostgreSQL - GROUP BY clause

Managing Tables

• PostgreSQL - CREATE TABLE
• PostgreSQL - SELECT INTO
• PostgreSQL - Create Auto-increment Column using SERIAL
• PostgreSQL - CREATE SEQUENCE
• PostgreSQL - Identity Column
• PostgreSQL - ALTER TABLE
• PostgreSQL - Rename Table
• PostgreSQL - ADD COLUMN
• PostgreSQL - DROP COLUMN
• PostgreSQL - Change Column Type
• PostgreSQL - RENAME COLUMN
• PostgreSQL - DROP TABLE
• PostgreSQL - TRUNCATE TABLE
• PostgreSQL - Temporary Table
• PostgreSQL - Temporary table name
• PostgreSQL - Removing Temporary Table
• PostgreSQL - Copy a Table
• PostgreSQL - Comparing Tables
• PostgreSQL - Describe Table
• PostgreSQL - Show Tables
• PostgreSQL - Import CSV File Into Table

Modifying Data

• PostgreSQL - INSERT
• PostgreSQL - Insert multiple rows
• PostgreSQL - UPDATE
• PostgreSQL - DELETE
• PostgreSQL - Upsert

Conditionals

• PostgreSQL - CASE
• PostgreSQL - COALESCE
• PostgreSQL - NULLIF() Function
• PostgreSQL - CAST

Control Flow

• PostgreSQL - IF Statement
• PostgreSQL - CASE Statement
• PostgreSQL - Loop Statement
• PostgreSQL - While Loops
• PostgreSQL - For Loops
• PostgreSQL - Exit
• PostgreSQL - Continue

Transactions & Constraints

• PostgreSQL - Transactions
• PostgreSQL - COMMIT
• PostgreSQL - BEGIN
• PostgreSQL - ROLLBACK
• PostgreSQL - Primary Key
• PostgreSQL - Foreign Key
• PostgreSQL - CHECK Constraint
• PostgreSQL - UNIQUE Constraint
• PostgreSQL - NOT NULL Constraint

Working with JOINS & Schemas

• PostgreSQL - Joins
• PostgreSQL - LEFT JOIN
• PostgreSQL - INNER JOIN
• PostgreSQL - FULL OUTER JOIN
• PostgreSQL - SELF JOIN
• PostgreSQL - Schema
• PostgreSQL - CREATE SCHEMA
• PostgreSQL - DROP SCHEMA
• PostgreSQL - ALTER SCHEMA

Roles & Permissions

• PostgreSQL - CREATE ROLE
• PostgreSQL - ALTER ROLE
• PostgreSQL - DROP ROLE
• PostgreSQL - GRANT
• PostgreSQL - REVOKE
• PostgreSQL - Role Membership

Working with Sets

• PostgreSQL - UNION operator
• PostgreSQL - INTERSECT Operator
• PostgreSQL - EXCEPT Operator
• PostgreSQL - GROUPING SETS
• PostgreSQL - CUBE
• PostgreSQL - ROLLUP

Subquery & CTEs

• PostgreSQL - ANY Operator
• PostgreSQL - ALL Operator
• PostgreSQL - EXISTS Operator
• PostgreSQL - CTE
• PostgreSQL - Deleting Duplicate Rows using Subquery

User-defined Functions

• PostgreSQL - CREATE FUNCTION Statement
• PostgreSQL - Function parameter modes
• PostgreSQL - Function Overloading
• PostgreSQL - Function that returns table
• PostgreSQL - Drop Function

Important In-Built Functions

• PostgreSQL - AVG() Function
• PostgreSQL - COUNT() Function
• PostgreSQL - MAX() Function
• PostgreSQL - MIN() Function
• PostgreSQL - SUM() Function
• PostgreSQL - FIRST_VALUE Function
• PostgreSQL - LAST_VALUE Function
• PostgreSQL - NTH_VALUE Function
• PostgreSQL - ROW_NUMBER Function
• PostgreSQL - CURRENT_DATE Function
• PostgreSQL - CURRENT_TIME Function
• PostgreSQL - EXTRACT Function
• PostgreSQL- CONCAT Function
• PostgreSQL - FORMAT Function
• PostgreSQL - UPPER function
• PostgreSQL- LOWER function
• PostgreSQL - REGEXP_MATCHES Function
• PostgreSQL - REGEXP_REPLACE Function
• PostgreSQL - REPLACE Function

PostgreSQL PL/pgSQL

• PostgreSQL - Dollar-Quoted String Constants
• PostgreSQL - Block Structure

Variables & Constants

• PostgreSQL - Variables
• PostgreSQL - Select Into
• PostgreSQL - Row type variables
• PostgreSQL - Record type variable
• PostgreSQL - Constants

Stored Procedures

• PostgreSQL - Introduction to Stored Procedures
• PostgreSQL - CREATE PROCEDURE
• PostgreSQL - Drop Procedure

Working with Triggers

• PostgreSQL - Trigger
• PostgreSQL - CREATE TRIGGER
• PostgreSQL - DROP TRIGGER
• PostgreSQL - ALTER TRIGGER
• PostgreSQL - Disabling a Trigger
• PostgreSQL - Enabling a Trigger

Working with Views & Indexes

• PostgreSQL - CREATE INDEX
• PostgreSQL - DROP INDEX
• PostgreSQL - List Indexes
• PostgreSQL - UNIQUE Index
• PostgreSQL - Partial Index
• PostgreSQL - Index On Expression
• PostgreSQL - REINDEX
• PostgreSQL - Multicolumn Indexes

Errors & Exception Handling

• PostgreSQL - Errors and Messages
• PostgreSQL - Exception Handling
• PostgreSQL - Assert

PostgreSQL - Copy Database

Copying a database in PostgreSQL can be useful for various reasons, such as creating backups, testing, and more. However, PostgreSQL does not have a direct SQL command like COPY DATABASE. Instead, you can achieve this by using a combination of the command-line tools provided by PostgreSQL or by other methods.

Here's how you can copy a database in PostgreSQL:

1. Using createdb and pg_dump:

• First, dump the source database to a file:

pg_dump -U username -h hostname sourcedb > backup.sql

• Create a new database:

createdb -U username -h hostname targetdb

• Restore the dump to the new database:

psql -U username -h hostname targetdb < backup.sql

2. Using the pg_dumpall Tool:

If you want to copy all databases (and roles), you can use pg_dumpall.

• Dump all databases:

pg_dumpall -U username > alldbs.sql

• Restore:

psql -U username -f alldbs.sql postgres

3. Using the CREATE DATABASE with TEMPLATE:

PostgreSQL allows you to create a new database by copying an existing database. This method requires the source database to be in a quiescent state for the copy duration.

• First, you need to disconnect all clients from the source database:

SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname = 'sourcedb';

• Use the CREATE DATABASE command with the TEMPLATE option:

CREATE DATABASE targetdb WITH TEMPLATE sourcedb OWNER dbowner;

Replace sourcedb with the name of the source database and targetdb with the name of the new database. dbowner should be the name of the database owner.

Considerations:

• Always backup your data before performing any operations.
• Ensure adequate disk space is available if copying large databases.
• Remember that when using the TEMPLATE option, no other connections can be active on the source database.
• When copying databases between different PostgreSQL servers or versions, the pg_dump and psql approach is generally more flexible and recommended.

Remember to adjust access controls and permissions as necessary after the copy, especially if this is being done in a production environment.

1. Copying a PostgreSQL database:

   • Description: Copying a PostgreSQL database involves creating a duplicate of the entire database, including its schema and data.
   • Code:

     pg_dump -U username -h localhost sourcedb > backup.sql
     createdb -U username -h localhost targetdb
     psql -U username -h localhost targetdb < backup.sql
     

2. Using pg_dump and pg_restore to copy a PostgreSQL database:

   • Description: pg_dump exports the database, and pg_restore imports it to create a copy.
   • Code:

     pg_dump -U username -h localhost sourcedb > backup.sql
     createdb -U username -h localhost targetdb
     pg_restore -U username -h localhost -d targetdb backup.sql
     

3. Cloning a PostgreSQL database to another server:

   • Description: Copying a database to another server involves using pg_dump and pg_restore with the appropriate connection parameters.
   • Code:

     pg_dump -U username -h source_host sourcedb > backup.sql
     createdb -U username -h target_host targetdb
     pg_restore -U username -h target_host -d targetdb backup.sql
     

4. Copying data and schema between PostgreSQL databases:

   • Description: Use pg_dump to export both data and schema and pg_restore to import into another database.
   • Code:

     pg_dump -U username -h localhost -C sourcedb > backup.sql
     createdb -U username -h localhost targetdb
     pg_restore -U username -h localhost -d targetdb backup.sql
     

5. Copying specific tables from one PostgreSQL database to another:

   • Description: Use pg_dump with the -t option to export specific tables.
   • Code:

     pg_dump -U username -h localhost -t table1 -t table2 sourcedb > backup.sql
     createdb -U username -h localhost targetdb
     pg_restore -U username -h localhost -d targetdb backup.sql
     

6. Copying a database with pg_basebackup in PostgreSQL:

   • Description: pg_basebackup creates a binary backup of the entire database cluster.
   • Code:

     pg_basebackup -U username -h localhost -D /path/to/targetdb
     

7. Duplicating a PostgreSQL database with pg_dumpall:

   • Description: pg_dumpall dumps the entire PostgreSQL cluster, including all databases and roles.
   • Code:

     pg_dumpall -U username -h localhost > backup.sql
     psql -U username -h localhost -f backup.sql
     

8. Handling user roles and permissions when copying a PostgreSQL database:

   • Description: Ensure roles and permissions are included in the dump using -x with pg_dump.
   • Code:

     pg_dump -U username -h localhost -x sourcedb > backup.sql
     

9. Managing sequences and serial columns when copying PostgreSQL databases:

   • Description: Use the --no-privileges and --no-owner options with pg_dump to avoid issues with sequences and serial columns.
   • Code:

     pg_dump -U username -h localhost --no-privileges --no-owner sourcedb > backup.sql