What if you have a facility in SQL Server that allows you to group these SQL objects to immediately look at the database and understand what objects are included in that domain? The schema in SQL Server does just that. Over the following few paragraphs, we will learn about SQL Schema definition, their advantage, disadvantage, and use. Let's dive more into what is schema in SQL Server database and learn more about their importance in SQL and key takeaways. You should check out the online SQL server training course and shape your ever-growing SQL career.
What is a Schema in SQL Server Database?
A schema is a list of logical data structures in a SQL database. A database user owns the schema with the same name as the database manager. SQL Server 2005 defines a schema as an individual entity (container of objects) distinct from the user who constructs the object.
SQL Schema Syntax
The syntax for SQL Schema is as follows
CREATE SCHEMA schemaname
[AUTHORIZATION ownername]
GO
Types of Database Schemas
There are three main types of database schemas:
Conceptual Database Schema: This is a high-level overview of what your database will contain, how the data will be organized, and the rules the data will follow. This type of schema is created in the initial project stage.A conceptual schema focuses on the main concepts and their relationships. It doesn’t dig into any details and is thus insufficient to build a database.
Logical Database Schema: This schema clearly defines all the elements within the database and any related information, such as field names, entity relationships, integrity constraints, and table names.A logical database schema states the logical rules or constraints that dictate how the elements within a database interact. The creation process for it varies depending on the project’s requirements.
Physical Database Schema: A physical schema combines contextual and logical information while adding technical requirements. It contains the syntax needed to create data structures within the disk storage.Both logical and physical schemas include a primary key that serves as a unique identifier for every entry in the table. Data is an integral part of SQL Server, and there’s great demand for sql administrators. Therefore, go through the SQL DBA career path if you want to set yourself up for this role.
Use of SQL Schema
The following are the advantages of SQL Schema
- Consistent data formatting
- Unique primary keys for every record entry
- Inclusion of all essential data
- A foreign key to defining the relationships between different entities
SQL Schema Example
How to create a schema
The syntax for creating SQL Schema is as below
CREATE SCHEMA schema_example;
GO
The following query lists out all the schemas in a database
SELECT *
FROM sys.schemas
The output looks like below
Let us now create a new table named Geektab in the geeks_sch schema:
CREATE TABLE geeks_sch.Geektab(
G_id INT PRIMARY KEY IDENTITY,
Name VARCHAR(200),
DOJ DATETIME2 IS NOT NULL
);
How to Alter a Schema?
The ALTER SCHEMA statement renames a schema or specifies a new owner, who must be a pre-existing database user.
The Syntax for Altering a Schema:
ALTER SCHEMA schema_name [RENAME TO new_schema_name] [OWNER TO new_user_name]
Here, new_schema_name refers to the name you want to rename the existing schema, and new_user_name refers to the new schema owner.
Example:
Suppose we want to rename the previously created schema- STUDENT as STUDENT_DETAILS and pass the ownership to new user DAVID. The following query will result in the desired result.
ALTER SCHEMA STUDENT [RENAME TO STUDENT_DETAILS] [OWNER TO DAVID]
How to Drop a Schema?
The DROP SCHEMA in SQL deletes all tables in that particular schema.
Syntax:
DROP SCHEMA <schema name>
Example:
If you want to delete the schema STUDENT_DETAILS, use the following SQL query.
DROP SCHEMA STUDENT_DETAILS
Advantages of SQL Schema
The advantage of SQL Schema is as below
- A SQL schema can be easily transferred to another user.
- Several users may share a schema.
- It enables you to transfer database objects between schemas.
- We gain greater power over the access and protection of database objects.
- A user can be removed without removing the database items connected to the user.
- Database objects can be grouped into logical groups using schemas. This is advantageous when several people collaborate on the same database program, and the architecture team needs to keep the database tables' credibility.
- Since a schema allows for the logical aggregation of database objects, it can assist us in cases where the database object name is the same but falls into a separate logical category.
Disadvantage of SQL Schema
The disadvantages of SQL Schema are as below.
Schemas can contribute to stereotypes and make it difficult to retain new information that does not conform to our established ideas about the world.
Conclusion
The above blog showcases Schema in SQL Server. It tells us what schema is, how to create it, and its advantages and disadvantages. This will be helpful for all the readers and encourage them to know more about schema. A comprehensive SQL server tutorial guide for beginners & experienced will help you understand what an SQL server is, basic SQL commands, and SQL server career path.
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