Updated May 30, 2023
Difference between PostgreSQL Database vs schema
PostgreSQL database is a container containing all the schemas, records, logs, and constraints of the table. Databases are rigidly separated, which means that a user cannot access two databases together. You actively use DML (Data Manipulation Language) commands to manipulate the data in the PostgreSQL database.
The PostgreSQL Schema actively defines the logical structure and storage of data within the database. It contains all the tables, data types, indexes, functions, stored procedures, and everything related. One can define the different Schema in a database for different people accessing the application to avoid conflicts and unnecessary interference. You can draw a schema diagram to illustrate the database schema of a table, showcasing its columns, data types, key constraints, and other relevant information.
Head to Head Comparison Between PostgreSQL Database vs schema (Infographics)
Below are the top 9 differences between PostgreSQL Database vs schema:
Comparison Table of PostgreSQL database vs schema
Below given is the comparison table showing the head to head comparison between the PostgreSQL database and schema:
| S.No. | PostgreSQL database | PostgreSQL schema |
|
1. |
A database in PostgreSQL contains the subset of schema. It has all the schemas, records, and constraints for tables. | A Schema in PostgreSQL is a namespace that contains all the named database objects like tables, indexes, data types, functions, stored procedures, etc. |
| 2. | One database can contain any number of schemas that have tables. | Schema, on the other hand, contains the objects like data types, functions, operators, views, indexes, etc. |
| 3. | Databases in PostgreSQL are rigidly separated, which means one cannot use two different databases together. To use any other database, one needs to connect to it and use it. | Unlike databases, schemas in PostgreSQL are not rigidly separated. This means that you can actively use and access objects from two or more schemas within the same database. |
| 4. | The database is the main container having all the log files, data, and other schemas. | Schema, on the other hand, is like the folder in the database used to group logical objects together. |
| 5. | A database is a collection of interrelated data and contains information about the considered object. | Schema is the logical representation of the entire database. |
| 6. | Databases in PostgreSQL can be updated frequently. | Once declared, Schema in PostgreSQL should not be changed frequently as it disturbs the whole data organization of how the relationships are created between different tables, related stored procedures, etc. |
| 7. | To actively modify the data in PostgreSQL, you use DML (Data Manipulation Language) statements. | To actively modify the data in a PostgreSQL Schema, you utilize DDL (Data Definition Language) statements. |
| 8. | Syntax to create a database in PostgreSQL is:
CREATE DATABASE db_name;
where, db_name is the name of the database created by the programmer. |
Syntax to create a schema in PostgreSQL is:
CREATE SCHEMA schema_name;
where, schema_name is the name of the schema to be created. |
| 9. | Syntax to drop a database in PostgreSQL is:
where, db_name is the database name-dropped by the superuser or database owner. |
Syntax to drop a schema in PostgreSQL is:
where, schema_name is the name of the schema to be deleted. CASCADE: It will automatically drop all the objects of the schema, like functions, tables, etc. RESTRICT: It will refuse to drop the schema if it contains objects like tables, functions, etc. By default, RESTRICT is set. |
Key Differences of PostgreSQL Database vs schema
Let’s explore some of the key differences between the PostgreSQL database and schema in detail:
1. Schema in a database is the logical representation of a database that describes the whole database. It contains views, indexes, tables, data types, operators, etc. The schema defines the attributes of the database. In contrast, a database is a container that contains all the schemas and logs, records all the related data and constraints for tables, and is an organized collection of interrelated data.
2. You actively use DML (Data Modification Language) statements such as INSERT, SELECT, UPDATE, and DELETE to modify data in a database. To modify the data in a PostgreSQL Schema, you use DDL (Data Definition Language) statements like CREATE, DROP, ALTER, TRUNCATE, and RENAME.
3. When considering modifications, the data in a database requires regular updates over time. You should minimize changes to the Schema as they can significantly impact various aspects such as table values, table relationships (primary key, foreign key), and associated stored procedures.
4. Schema in PostgreSQL uses the logical structure to store the data, but on the other hand, the database uses physical memory to store the data.
5. As we have already said, the database contains all the schemas and the logs, and Schema contains all the tables, fields, indexes, etc. So the programmer can not create two tables with the same name in one schema. Though, it can be done in two different schemas. But it is possible that the user creates 2 tables with the same name in two different databases. As both databases are independent and not related to each other.
6. One cannot use two different databases together. To switch the database, the programmer needs to disconnect the previous one and connect the new one to use its tables and other related data, whereas it is possible to access 2 different schemas together if they have the privilege to do so.
7. Schemas typically organize the data in a database logically and structurally, making it easily accessible and manageable. Moreover, it allows multiple users to access a single database without interfering with each other. So Schemas play an important role when multiple users are using the application and accessing the database in their own way or multiple applications are using the same one. On the other hand, the database contains all the Schemas created for different users.
Conclusion
The above description clearly explains the PostgreSQL database and schema and the major difference between the two. For a programmer working on a database, it is important to deeply understand basic concepts like database, schema, various data types, fields, etc., to have a clear understanding while working on real databases.
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