Create schema должна быть первой инструкцией в пакетном запросе

Ага, я тоже сначала первым способом подумала, потом поняла, что имя БД это не строковая переменная, и так не получится.

Спасибо! Вы — гений! Все работает!!! Есть еще вопрос. Сейчас тему создам другую.

Добавлено через 22 часа 41 минуту
Ох… Работает на маленьком коде, а с большим какие-то проблемы, даже не пойму чего от меня хотят Вот кусок кода:

SQL 
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DECLARE @DBName nvarchar(250)
SET @DBName = 'test'
 
DECLARE @SQLText nvarchar(MAX)
 
SET @SQLText = 
'/****** Object:  Database {DBNAME}    Script Date: 02/27/2013 10:56:41 ******/
CREATE DATABASE {DBNAME} ON  PRIMARY 
( NAME = N''zinc'', FILENAME = N''c:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\DATA\{DBNAME}.mdf'' , SIZE = 1087488KB , MAXSIZE = UNLIMITED, FILEGROWTH = 1024KB )
 LOG ON 
( NAME = N''zinc_log'', FILENAME = N''c:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\DATA\{DBNAME}.ldf'' , SIZE = 2876352KB , MAXSIZE = 2048GB , FILEGROWTH = 10%)
 
ALTER DATABASE {DBNAME} SET COMPATIBILITY_LEVEL = 100
 
IF (1 = FULLTEXTSERVICEPROPERTY(''IsFullTextInstalled''))
begin
EXEC {DBNAME}.[dbo].[sp_fulltext_database] @action = ''enable''
end'
SET  @SQLText = REPLACE (@SQLText ,  '{DBNAME}' ,  @DBName) 
EXECUTE  (@SQLText)
 
SET @SQLText = 
'ALTER DATABASE {DBNAME} SET ANSI_NULL_DEFAULT OFF
 
ALTER DATABASE {DBNAME} SET ANSI_NULLS OFF
 
ALTER DATABASE {DBNAME} SET ANSI_PADDING OFF
 
ALTER DATABASE {DBNAME} SET ANSI_WARNINGS OFF
 
ALTER DATABASE {DBNAME} SET ARITHABORT OFF
 
ALTER DATABASE {DBNAME} SET AUTO_CLOSE OFF
 
ALTER DATABASE {DBNAME} SET AUTO_CREATE_STATISTICS ON
 
ALTER DATABASE {DBNAME} SET AUTO_SHRINK OFF
 
ALTER DATABASE {DBNAME} SET AUTO_UPDATE_STATISTICS ON
 
ALTER DATABASE {DBNAME} SET CURSOR_CLOSE_ON_COMMIT OFF
 
ALTER DATABASE {DBNAME} SET CURSOR_DEFAULT  GLOBAL
 
ALTER DATABASE {DBNAME} SET CONCAT_NULL_YIELDS_NULL OFF
 
ALTER DATABASE {DBNAME} SET NUMERIC_ROUNDABORT OFF
 
ALTER DATABASE {DBNAME} SET QUOTED_IDENTIFIER OFF
 
ALTER DATABASE {DBNAME} SET RECURSIVE_TRIGGERS OFF
 
ALTER DATABASE {DBNAME} SET  DISABLE_BROKER
 
ALTER DATABASE {DBNAME} SET AUTO_UPDATE_STATISTICS_ASYNC OFF
 
ALTER DATABASE {DBNAME} SET DATE_CORRELATION_OPTIMIZATION OFF
 
ALTER DATABASE {DBNAME} SET TRUSTWORTHY OFF
 
ALTER DATABASE {DBNAME} SET ALLOW_SNAPSHOT_ISOLATION OFF
 
ALTER DATABASE {DBNAME} SET PARAMETERIZATION SIMPLE
 
ALTER DATABASE {DBNAME} SET READ_COMMITTED_SNAPSHOT OFF
 
ALTER DATABASE {DBNAME} SET HONOR_BROKER_PRIORITY OFF
 
ALTER DATABASE {DBNAME} SET  READ_WRITE
 
ALTER DATABASE {DBNAME} SET RECOVERY FULL
 
ALTER DATABASE {DBNAME} SET  MULTI_USER
 
ALTER DATABASE {DBNAME} SET PAGE_VERIFY CHECKSUM
 
ALTER DATABASE {DBNAME} SET DB_CHAINING OFF
 
USE {DBNAME}
 
/****** Object:  User [test]    Script Date: 02/27/2013 10:56:41 ******/
CREATE USER [test] WITHOUT LOGIN WITH DEFAULT_SCHEMA=[dbo]
 
/****** Object:  User [Access]    Script Date: 02/27/2013 10:56:41 ******/
CREATE USER [Access] WITHOUT LOGIN WITH DEFAULT_SCHEMA=[dbo]
 
/****** Object:  Schema [journal]    Script Date: 02/27/2013 10:56:41 ******/
CREATE SCHEMA [journal] AUTHORIZATION [dbo]
 
/****** Object:  Schema [config]    Script Date: 02/27/2013 10:56:41 ******/
CREATE SCHEMA [config] AUTHORIZATION [dbo] ............ и т.д.'
 
SET  @SQLText = REPLACE (@SQLText ,  '{DBNAME}' ,  @DBName) 
EXECUTE  (@SQLText)

Первая ошибка, которую он выдает: «CREATE SCHEMA должна быть первой инструкцией в пакетном запросе.»

Что я не так делаю? Второй день голову ломаю.

Простите за мою глупость, но я честно делала как только могла, и никак не могу понять в чем проблема

Источник

Basically its what the title says. This is my code.

USE Assignment2;
GO

/* Player View (2 marks)
    Create a view which shows the following details of all players:
        • The ID number of the player
        • The first name and surname of the player concatenated and given an alias of “full_name”
        • The team ID number of the player (if applicable)
        • The team name of the player (if applicable)
        • The coach ID number of the player (if applicable)
        • The name of the player’s coach (if applicable)

   Creating this view requires a select statement using multiple joins and concatenation of names.  
   Make sure that you use the appropriate type of join to ensure that players without teams or coaches are still included in the results.

*/


-- Write your Player View here
PRINT 'Creating Player View'

CREATE VIEW playerView AS 
SELECT player.id, player.firstName + ' ' + player.surname AS 'Full name', player.team, team.name, player.coach, coach.firstName, coach.surname 
FROM player
LEFT OUTER JOIN team
    ON player.team = team.id
    LEFT OUTER JOIN player as coach
        ON player.coach = coach.id;



GO
/* Race View (3 marks)
   Create a view which shows the following details of all races:
        • All of the columns in the race table
        • The name of the race type, course and team involved in the race
        • The full name of the player observing the race and the full name of the MVP (if applicable)
        • A calculated column with an alias of “unpenalised_score”, which adds the points penalised to the final score

   Creating this view requires a select statement using multiple joins and concatenation of names.  
   Make sure that you use the appropriate type of join to ensure that races without MVPs are still included in the results.
*/

-- Write your Race View here
PRINT 'Creating Race View'

CREATE VIEW raceView AS 
SELECT race.id, race.dateOfRace, race.raceType, raceType.name AS raceTypeName, race.course, course.name AS courseName, race.team, team.name AS teamName, race.observer, obs.firstName + ' ' + obs.surname AS observer_name, race.mvp, mvp.firstName + ' ' + mvp.surname AS mvp_name, race.pointsPenalised, race.finalScore + race.pointsPenalised AS unpenalised_score, race.finalScore
FROM race
INNER JOIN raceType
    ON race.raceType = raceType.id
    INNER JOIN course
        ON race.course = course.id
        INNER JOIN team
            ON race.team = team.id
            LEFT OUTER JOIN player AS mvp
                ON race.mvp = mvp.id
                LEFT OUTER JOIN player AS obs
                    ON race.observer = obs.id;
GO 

SELECT * 
FROM playerView

SELECT *
FROM raceView


/* Additional Information:
   The views are very convenient replacements for the tables they represent, as they include the names and calculated values that you will often need in queries.
   You are very much encouraged to use the views to simplify the queries that follow.  You can use a view in a SELECT statement in exactly the same way as you can use a table.

   If you wish to create additional views to simplify the queries which follow, include them in this file.
*/

When I run each CREATE VIEW separately, it seems to run it correctly with no errors. But when I try to run the entire script, it gives me this error.

Msg 111, Level 15, State 1, Line 20
‘CREATE VIEW’ must be the first statement in a query batch.
Msg 111, Level 15, State 1, Line 15
‘CREATE VIEW’ must be the first statement in a query batch.
Msg 208, Level 16, State 1, Line 2
Invalid object name ‘playerView’.

Before attempting to run this script, I first delete database, recreate the tables, populate them and then run this script.

Any ideas where I’m going wrong?

Источник

Problem

When you’re executing a CREATE/ALTER statement to create a procedure/view/function/trigger, you get one of the following errors:

‘CREATE/ALTER PROCEDURE’ must be the first statement in a query batch

‘CREATE VIEW’ must be the first statement in a query batch.

‘CREATE FUNCTION’ must be the first statement in a query batch.

‘CREATE TRIGGER’ must be the first statement in a query batch.

You can’t execute these CREATE/ALTER statements with other statements.

Solution

The solution is to execute the CREATE/ALTER statement separately from other statements. How you do that depends on if you’re using SSMS/sqlcmd/osql or executing from C#.

If you’re executing from SSMS (or sqlcmd/osql)

Add the keyword GO right before CREATE statement. This is the default batch separator in SSMS. It splits the query into multiple batches. In other words, it executes the CREATE statement by itself in its own batch, therefore solving the problem of it needing to be the first statement in a batch. Here’s an example:

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'spGetAllPosts') AND type in (N'P', N'PC'))
	DROP PROCEDURE [dbo].spGetAllPosts
GO
CREATE PROCEDURE [dbo].spGetAllPosts
AS
BEGIN
    SELECT * FROM Posts
END
Code language: SQL (Structured Query Language) (sql)

If you’re executing from C#

You can’t use the GO keyword in C#. Instead you have to execute the SQL queries separately. The best way to do that is to execute the first part, then change the CommandText and execute the second part.

using System.Data.SqlClient;

string dropProcQuery = 
	@"IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'spGetAllPosts') AND type in (N'P', N'PC'))
		DROP PROCEDURE[dbo].spGetAllPosts";
		
string createProcQuery = 
	@"CREATE PROCEDURE [dbo].spGetAllPosts
	AS
	BEGIN
		SELECT * FROM Posts
	END";
	
using (var con = new SqlConnection(ConnectionString))
{
	using (var cmd = new SqlCommand(dropProcQuery, con))
	{
	        //Execute the first statement
		con.Open();
		cmd.ExecuteNonQuery();
		
		//Then execute the CREATE statement
		cmd.CommandText = createProcQuery;
		cmd.ExecuteNonQuery();
	}
}

Code language: C# (cs)

Related Articles

Источник

Database Schema

A schema is a logical database object holder. A database schema of a database system is its structure described in a formal language supported by the database management system. The formal definition of a database schema is a set of formulas (sentences) called integrity constraints imposed on a database. These integrity constraints ensure compatibility between parts of the schema. All constraints are expressible in the same language.
Creating schemas can be useful when objects have circular references, that is when we need to create two tables each with a foreign key referencing the other table. Different implementations treat schemas in slightly different ways.

Syntax:

CREATE SCHEMA [schema_name] [AUTHORIZATION owner_name]
[DEFAULT CHARACTER SET char_set_name]
[PATH schema_name[, ...]]
[ ANSI CREATE statements [...] ]
[ ANSI GRANT statements [...] ];

Parameter:

Name Description
schema_name The name of a schema to be created. If this is omitted, the user_name is used as the schema name.
AUTHORIZATION owner_name Identifies the user who is the owner of the schema. If not mentioned the current user is set as the owner.
DEFAULT CHARACTER SET char_set_name Specify the default character set, used for all objects created in the schema.
PATH schema_name[, …] An optional file path and file name.
ANSI CREATE statements […] Contains one or more CREATE statements.
ANSI GRANT statements […] Contains one or more GRANT statements.

Examples :

Example-1: As a user with authority, create a schema called STUDENT with the user STUDENT as the owner.

SQL Code:

CREATE SCHEMA STUDENT AUTHORIZATION STUDENT

Example-2: Create a schema that has an student details table. Give authority on the table to user DAVID.

SQL Code:

-- Creating a new schema named INVENTRY
CREATE SCHEMA INVENTRY;

-- Creating a table named PART within the INVENTRY schema
-- The table has three columns: IDNO (SMALLINT), SNAME (VARCHAR with a maximum length of 40 characters), and CLASS (INTEGER)
CREATE TABLE PART (
    IDNO   SMALLINT NOT NULL,
    SNAME  VARCHAR(40),
    CLASS  INTEGER
);

-- Granting all privileges on the PART table to the user DAVID
GRANT ALL ON PART TO DAVID;

Explanation:

In the above example –

 
CREATE SCHEMA INVENTRY;

The above line creates a new schema (a logical container for database objects) named «INVENTRY.» Schemas are used to organize database objects like tables, views, etc.

CREATE TABLE PART (
    IDNO   SMALLINT NOT NULL,
    SNAME  VARCHAR(40),
    CLASS  INTEGER
);

This section creates a table named «PART» within the «INVENTRY» schema. The table has three columns:

  • IDNO with a data type of SMALLINT that cannot contain NULL values (NOT NULL constraint).
  • SNAME with a data type of VARCHAR(40) which can store variable-length character strings of up to 40 characters.
  • CLASS with a data type of INTEGER.
GRANT ALL ON PART TO DAVID;

The above line grants all permissions (such as SELECT, INSERT, UPDATE, DELETE) on the «PART» table to a user or role named «DAVID.» The user «DAVID» will now have full access to the «PART» table in the «INVENTRY» schema.

Create schema in MySQL [8.2]

In MySQL, CREATE SCHEMA is a synonym for CREATE DATABASE.

Syntax: 

CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name
    [create_specification] ...

create_specification:
    [DEFAULT] CHARACTER SET [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name

Explanation:

This SQL syntax is used to create a new database or schema in a database management system. Below is an explanation of the syntax:

  • CREATE DATABASE or CREATE SCHEMA: This part of the syntax indicates whether a new database or schema is being created. In most database systems, the terms «database» and «schema» are used interchangeably, but some systems differentiate between them.
  • IF NOT EXISTS (optional): This clause is used to specify that the database or schema should be created only if it does not already exist. If the database or schema with the specified name already exists, the command will not produce an error.
  • db_name: This is the name of the database or schema that is being created. It should be a valid identifier and should not conflict with any existing databases or schemas.
  • create_specification (optional): This part of the syntax allows for specifying additional options for creating the database or schema. Currently, two options are supported:
    • DEFAULT CHARACTER SET [=] charset_name: This option specifies the default character set to be used for storing character data in the database or schema. The charset_name parameter specifies the name of the character set. Character sets define the encoding of characters used in the database.
    • DEFAULT COLLATE [=] collation_name: This option specifies the default collation to be used for comparing and sorting character data in the database or schema. The collation_name parameter specifies the name of the collation. Collations define the rules for comparing and sorting characters based on their encoding and language-specific rules.

Create schema in PostgreSQL 16.1

CREATE SCHEMA enters a new schema into the current database. The schema name must be distinct from the name of any existing schema in the current database.

Syntax:

CREATE SCHEMA schema_name [ AUTHORIZATION user_name ] [ schema_element [ ... ] ]
CREATE SCHEMA AUTHORIZATION user_name [ schema_element [ ... ] ]
CREATE SCHEMA IF NOT EXISTS schema_name [ AUTHORIZATION user_name ]
CREATE SCHEMA IF NOT EXISTS AUTHORIZATION user_name

Explanation:

  • In PostgreSQL, the CREATE SCHEMA statement is used to create a new schema within the current database.
  • A schema is a collection of database objects (such as tables, views, functions) that allows you to logically organize and manage your database objects.
  • The different variations of the CREATE SCHEMA statement allow for various scenarios:
    • CREATE SCHEMA schema_name: Creates a new schema with the specified name.
    • CREATE SCHEMA AUTHORIZATION user_name: Creates a new schema owned by the specified user.
    • CREATE SCHEMA IF NOT EXISTS schema_name: Creates a new schema with the specified name only if it does not already exist.
    • CREATE SCHEMA IF NOT EXISTS AUTHORIZATION user_name: Creates a new schema owned by the specified user only if it does not already exist.
  • Optionally, you can specify the user who will own the schema using the AUTHORIZATION clause.
  • Additionally, you can include schema elements such as tables, views, or other database objects within the CREATE SCHEMA statement. These elements will be created within the newly created schema.

Create schema in Oracle 19c

Use the CREATE SCHEMA statement to create multiple tables and views and perform multiple grants in your own schema in a single transaction.
To execute a CREATE SCHEMA statement, Oracle Database executes each included statement. If all statements execute successfully, then the database commits the transaction. If any statement results in an error, then the database rolls back all the statements.

The CREATE SCHEMA statement can include CREATE TABLE, CREATE VIEW, and GRANT statements. To issue a CREATE SCHEMA statement, you must have the privileges necessary to issue the included statements.

Syntax: 

CREATE SCHEMA AUTHORIZATION schema
   { create_table_statement
   | create_view_statement
   | grant_statement
   }...;

Explanation:

  • CREATE SCHEMA: This keyword initiates the creation of a schema. In Oracle SQL, a schema is a logical container for database objects such as tables, views, indexes, etc. It does not necessarily correspond to a user account; rather, it’s a namespace that contains database objects.
  • AUTHORIZATION schema: This clause specifies the name of the user who will own the schema being created. The user specified in this clause becomes the schema owner and has full control over the objects within the schema.
  • { create_table_statement | create_view_statement | grant_statement }: These are the statements or commands that define the structure and permissions of the objects within the schema. Multiple statements can be included within the CREATE SCHEMA block to create tables, views, or grant permissions to other users.
    • create_table_statement: This statement is used to create tables within the schema. It defines the structure of the tables, including column names, data types, constraints, etc.
    • create_view_statement: This statement is used to create views within the schema. Views are virtual tables that present data from one or more underlying tables or views in a structured format.
    • grant_statement: This statement is used to grant privileges or permissions on the objects within the schema to other users or roles. It specifies the type of access (e.g., SELECT, INSERT, UPDATE, DELETE) that is granted to specific users or roles.

Create schema in SQL Server 2022

Creates a schema in the current database. The CREATE SCHEMA transaction can also create tables and views within the new schema, and set GRANT, DENY, or REVOKE permissions on those objects.

Syntax:

The following statement creates a database and fully specifies each argument :

CREATE SCHEMA schema_name_clause [ <schema_element> [ ...n ] ]

<schema_name_clause> ::=
    {
    schema_name
    | AUTHORIZATION owner_name
    | schema_name AUTHORIZATION owner_name
    }

<schema_element> ::= 
    { 
        table_definition | view_definition | grant_statement | 
        revoke_statement | deny_statement 
    }

Explanation:

  • This SQL Server code snippet outlines the syntax for creating a schema and defining its elements.
  • CREATE SCHEMA schema_name_clause: This statement initiates the creation of a schema with the specified name clause.
  • <schema_name_clause>: This section outlines the possible clauses that can be part of the schema creation:
    • schema_name: Specifies the name of the schema being created.
    • AUTHORIZATION owner_name: Assigns ownership of the schema to the specified owner.
    • schema_name AUTHORIZATION owner_name: Combines both schema name and authorization clauses.
  • : This section specifies the elements that can be included within the schema:
    • table_definition: Defines the structure of tables within the schema, including column names, data types, constraints, etc.
    • view_definition: Specifies the definition of views within the schema. Views are virtual tables that present data from underlying tables or views.
    • grant_statement: Grants permissions on schema objects to users or roles.
    • revoke_statement: Revokes previously granted permissions.
    • deny_statement: Explicitly denies permissions on schema objects.
    • These elements allow for the definition of various schema components, including tables, views, and permissions.

Alter Schema

The ALTER SCHEMA statement is used to rename a schema or to specify a new owner, the new owner must be a pre-existing user on the database

Syntax: 

ALTER SCHEMA schema_name [RENAME TO new_schema_name] [OWNER TO new_user_name]

Parameter:

Name Description
schema_name The name of an existing schema.
new_schema_name The new name of the schema.
new_owner The new owner of the schema.

Alter Schema in MySQL [8.2]

In MySQL, CREATE SCHEMA is a synonym for CREATE DATABASE.

Syntax: 

ALTER {DATABASE | SCHEMA} [db_name]
    alter_specification ...
ALTER {DATABASE | SCHEMA} db_name
    UPGRADE DATA DIRECTORY NAME

alter_specification:
    [DEFAULT] CHARACTER SET [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name

In MySQL, ALTER SCHEMA is a synonym for ALTER DATABASE. ALTER DATABASE enables you to change the overall characteristics of a database. These characteristics are stored in the db.opt file in the database directory. To use ALTER DATABASE, you need the ALTER privilege on the database.

Explanation:

This MySQL syntax is used to alter a database or schema, modifying its characteristics or upgrading its data directory name.

  • ALTER DATABASE or ALTER SCHEMA: This part of the syntax specifies whether you are altering a database or a schema. In MySQL, databases and schemas are often used interchangeably.
  • [db_name]: This optional part of the syntax specifies the name of the database or schema that you want to alter.
  • alter_specification: This part of the syntax specifies the alterations you want to make to the database or schema. It includes:
    • [DEFAULT] CHARACTER SET [=] charset_name: This clause specifies the default character set to be used for storing character data in the database or schema. The charset_name parameter specifies the name of the character set. Character sets define the encoding of characters used in the database.
    • [DEFAULT] COLLATE [=] collation_name: This clause specifies the default collation to be used for comparing and sorting character data in the database or schema. The collation_name parameter specifies the name of the collation. Collations define the rules for comparing and sorting characters based on their encoding and language-specific rules.
  • UPGRADE DATA DIRECTORY NAME: This clause is used to upgrade the data directory name associated with the database or schema specified by db_name. It changes the name of the directory where the data files for the database or schema are stored. This operation is useful when you need to rename the directory containing the data files for the database or schema.

    Alter schema in PostgreSQL 16.1

    Description ALTER SCHEMA changes the definition of a schema. The user must own the schema to use ALTER SCHEMA. To rename a schema you must also have the CREATE privilege for the database. To alter the owner, you must also be a direct or indirect member of the new owning role, and you must have the CREATE privilege for the database.

    Syntax:

    ALTER SCHEMA name RENAME TO new_name
ALTER SCHEMA name OWNER TO new_owner

    Explanation:

    In PostgreSQL 16.1, the ALTER SCHEMA statement is used to modify existing schemas. Below is an explanation of the provided code snippets:

    • ALTER SCHEMA name RENAME TO new_name:
      • This statement is used to rename an existing schema.
      • name is the current name of the schema that you want to rename.
      • new_name is the new name that you want to assign to the schema.
      • This operation allows you to change the name of the schema without affecting its contents or dependencies.
    • ALTER SCHEMA name OWNER TO new_owner:
      • This statement is used to change the owner of an existing schema.
      • name is the name of the schema for which you want to change the owner.
      • new_owner is the name of the new owner to whom you want to transfer ownership of the schema.
      • The new owner will have full control over the schema and its contents, including the ability to modify or drop objects within the schema.

    Alter schema in SQL Server 2022

    ALTER SCHEMA can only be used to move securable between schemas in the same database. Users and schemas are completely separate.

    Syntax:

    ALTER SCHEMA schema_name 
   TRANSFER [ <entity_type> :: ] securable_name 
[;]

<entity_type> ::=
    {
    Object | Type | XML Schema Collection
    }

    Explanation:

    In SQL Server, the ALTER SCHEMA statement with the TRANSFER clause is used to transfer ownership of a securable object from one schema to another.

    • ALTER SCHEMA schema_name: This part of the statement specifies the schema from which the ownership of the securable object will be transferred.
    • TRANSFER: This keyword indicates that ownership of the specified securable object will be transferred.
    • [ :: ]: This is an optional clause that specifies the type of the securable object. It allows you to transfer ownership of different types of objects within the schema. The available entity types are:
      • Object: Refers to regular database objects such as tables, views, stored procedures, functions, etc.
      • Type: Refers to user-defined data types.
      • XML Schema Collection: Refers to XML schema collections.
    • securable_name: This is the name of the securable object whose ownership will be transferred. It can be prefixed with the entity type if specified.
    • The statement allows for transferring ownership of securable objects between schemas, providing flexibility in managing schema ownership and access control in the database.
    • The ALTER SCHEMA statement with TRANSFER clause is commonly used when reorganizing database schemas, consolidating objects under a different schema, or when ownership needs to be changed for security or organizational reasons.

    Drop Schema

    Destroy a schema.

    Syntax:

    DROP SCHEMA <schema name>

    Drop Schema in MySQL [8.2]

    DROP DATABASE drops all tables in the database and deletes the database. DROP SCHEMA is a synonym for DROP DATABASE.

    Syntax:

    DROP {DATABASE | SCHEMA} [IF EXISTS] db_name

    Explanation:

    • DROP DATABASE or DROP SCHEMA: This part of the syntax specifies whether you are dropping a database or a schema. In MySQL, databases and schemas are often used interchangeably.
    • [IF EXISTS]: This clause is optional and allows you to specify that the database or schema should be dropped only if it exists. If the database or schema does not exist and this clause is present, the DROP statement will not produce an error.
    • db_name: This is the name of the database or schema that you want to drop. It should be a valid identifier and must not contain any spaces or special characters.

      • The statement allows you to delete a database or schema from the MySQL server. Dropping a database or schema removes all its associated objects, such as tables, views, indexes, etc., and the data stored within them.

    • Caution should be exercised when using the DROP statement, as it permanently deletes the database or schema and its contents. It is recommended to use the IF EXISTS clause to prevent errors if the database or schema does not exist, especially in scripts or automated processes.

    Drop schema in PostgreSQL 16.1

    DROP SCHEMA removes schemas from the database. A schema can only be dropped by its owner or a superuser.

    Syntax:

    DROP SCHEMA [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]

    Explanation:

    • DROP SCHEMA: This is the beginning of the statement, indicating that you want to drop one or more schemas from the database.
    • [ IF EXISTS ]: This clause is optional. If specified, it ensures that the statement does not produce an error if the specified schemas do not exist in the database.
    • name [, …]: This part specifies the name or names of the schemas that you want to drop. You can specify multiple schema names separated by commas.
    • [ CASCADE | RESTRICT ]: These are optional clauses specifying the behavior of the drop operation when there are dependent objects within the schema(s) being dropped:
      • CASCADE: If specified, it automatically drops all objects (tables, views, functions, etc.) that are contained within the schema(s) being dropped. This includes dropping dependent objects recursively.
      • RESTRICT: If specified, it prevents the drop operation if there are any dependent objects within the schema(s) being dropped. The drop operation will fail if there are any dependent objects.
    • The statement allows you to delete one or more schemas from the PostgreSQL database. Dropping a schema removes all objects contained within it, including tables, views, functions, etc. However, it’s important to note that dropping a schema does not delete the data stored in the tables; it only removes the schema structure and associated objects.
    • The optional CASCADE and RESTRICT clauses provide control over how the drop operation behaves when there are dependent objects within the schema(s) being dropped, allowing you to customize the behavior according to your requirements.

    Drop schema in SQL Server 2022

    Conditionally drops the schema only if it already exists.

    Syntax: 

    DROP SCHEMA  [ IF EXISTS ] schema_name

    Explanation:

    • DROP SCHEMA: This is the beginning of the statement, indicating that you want to drop a schema from the database.
    • [ IF EXISTS ]: This clause is optional. If specified, it ensures that the statement does not produce an error if the specified schema does not exist in the database. If the schema exists, it will be dropped. If it doesn’t exist, no action will be taken.
    • schema_name: This specifies the name of the schema that you want to drop from the database. It should be a valid schema name in the database.
    • The statement allows you to delete a schema from the SQL Server database. Dropping a schema removes the schema and all objects contained within it, such as tables, views, stored procedures, and functions.
    • Caution should be exercised when using the DROP SCHEMA statement, as it permanently deletes the schema and its contents. It is recommended to use the IF EXISTS clause to prevent errors if the schema does not exist, especially in scripts or automated processes.

    Check out our 1000+ SQL Exercises with solution and explanation to improve your skills.

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20 August 2020

The CREATE SCHEMA operator does not actually create the circuit in Oracle. (Learn how to create a schema in Oracle.)

The CREATE SCHEMA statement is only used to create objects (i.e. tables, views) in your schema in one SQL statement instead of running the individual CREATE TABLE and CREATE VIEW statements.

If an error occurs when creating any of the objects in the CREATE SCHEMA statement, the Oracle database rolls back all creation operations (i.e. tables and views) in the CREATE SCHEMA statement.

Syntax of the CREATE SCHEMA operator

CREATE SCHEMA AUTHORIZATION schema_name
[create_table_statement]
[create_view_statement]
[grant_statement];

Parameters and arguments of the operator

  • schema_name – the name of the schema (which is the same as the Oracle user you logged on with).
  • create_table_statement – optional. This is a valid CREATE TABLE operator.
  • create_view_statement is optional. This is a valid CREATE VIEW operator.
  • grant_statement is optional. This is a valid GRANT operator.

Below is the CREATE SCHEMA operator (creating one table in the schematic):

CREATE SCHEMA AUTHORIZATION samvel
CREATE TABLE products
( product_id number(10) not null,
product_name varchar2(50) not null,
category varchar2(50),
CONSTRAINT products_pk PRIMARY KEY (product_id)
);

In this example, a scheme called samvel is created. In this new scheme, one table is created, called products.

You can also create multiple tables using the CREATE SCHEMA operator as follows:

CREATE SCHEMA AUTHORIZATION samvel
CREATE TABLE products
( product_id number(10) not null,
product_name varchar2(50) not null,
category varchar2(50),
CONSTRAINT products_pk PRIMARY KEY (product_id)
)
CREATE TABLE suppliers
( supplier_id number(10) not null,
supplier_name varchar2(50) not null,
city varchar2(25),
CONSTRAINT suppliers_pk PRIMARY KEY (supplier_id)
);

This CREATE SCHEMA operator will create two tables, the products and the suppliers. If an error occurs when creating any of these tables, no table will be created.

Alternatively, you could create these 2 tables using two separate CREATE TABLE operators as follows (as long as you are a samvel user):

CREATE TABLE products
( product_id number(10) not null,
product_name varchar2(50) not null,
category varchar2(50),
CONSTRAINT products_pk PRIMARY KEY (product_id)
);

CREATE TABLE suppliers
( supplier_id number(10) not null,
supplier_name varchar2(50) not null,
city varchar2(25),
CONSTRAINT suppliers_pk PRIMARY KEY (supplier_id)
);

What is an Oracle Schema – Database Tutorial – Oracle DBA Tutorial

Tags: Oracle, Oracle Database, Oracle SQL, PL/SQL, PLSQL, SQL

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