In SQL Server, you cannot drop a table if it is referenced by a FOREIGN KEY constraint. You have to either drop the child tables before removing the parent table, or remove foreign key constraints.
SQL Drop Column Syntax
- ALTER TABLE "table_name" DROP "column_name";
- ALTER TABLE "table_name" DROP COLUMN "column_name";
- ALTER TABLE Customer DROP Birth_Date;
- ALTER TABLE Customer DROP COLUMN Birth_Date;
- ALTER TABLE Customer DROP COLUMN Birth_Date;
Select all of the tables in your database in the Schema Browser clicking on the first table, holding Shift, and clicking on the last table. Right-click on the selected tables and select “Drop (n) Tables…†Click on Review SQL, as we will need to add in the foreign key check disable and enable.
To drop a single table,
enter DROP TABLE "S". "X" , where S is the schema and X is the table name. To drop several tables, enter DROP TABLE "S".
To get a list of all the tables in the public schema:
- Execute the following SQL query: SELECT 'DROP TABLE "' + schemaname + '".
- Copy the results, not including the header.
The query below will return a statement that can be used to drop all the tables which are present in the current user A's schema (normal scenario). select 'drop '||object_type||' '|| object_name || ';' from user_objects where object_type in ('VIEW','PACKAGE','SEQUENCE', 'PROCEDURE', 'FUNCTION', 'INDEX');
Introduction to Oracle DROP TABLESPACE statementFirst, specify the name of the tablespace that you want to drop after the DROP TABLESPACE keywords. Second, use the INCLUDE CONTENTS to delete all contents of the tablespace. If the tablespace has any objects, you must use this option to remove the tablespace.
When
DBCA deletes a database, it shuts down the database instance and then deletes all database files.
To delete a database using DBCA:
- Start DBCA as described in "Starting DBCA".
- In the Database Operation window, select Delete Database and click Next.
- Select the database to delete and click Next.
First, you specify the name of the table from which you want to delete data. Second, you specify which row should be deleted by using the condition in the WHERE clause. If you omit the WHERE clause, the Oracle DELETE statement removes all rows from the table.
Dropping a table removes the table definition from the data dictionary. All rows of the table are no longer accessible. All indexes and triggers associated with a table are dropped. All synonyms for a dropped table remain, but return an error when used.
How to safely delete SQL database objects
- Open SQL Server Management Studio.
- Right click the object that is to be deleted and select the Delete option from the drop down list:
- In the Delete object dialog, click the Show dependencies button:
Answer: DROP is used to delete a whole database or just a table. The DROP statement destroys the objects like an existing database, table, index, or view. A DROP statement in SQL removes a component from a relational database management system (RDBMS).
SQL Server DROP TABLE
- First, specify the name of the table to be removed.
- Second, specify the name of the database in which the table was created and the name of the schema to which the table belongs. The database name is optional.
- Third, use IF EXISTS clause to remove the table only if it exists.
We use the SQL DROP Table command to drop a table from the database. It completely removes the table structure and associated indexes, statistics, permissions, triggers and constraints.
1. The DROP command is used to remove table definition and its contents. Whereas the TRUNCATE command is used to delete all the rows from the table.
To drop foreign key (referential) constraints, use the DROP CONSTRAINT clause of the ALTER TABLE statement. When a foreign key constraint is dropped, packages or cached dynamic statements containing the following might be marked as invalid: Statements that insert or update the table containing the foreign key.
Explanation: The SQL TRUNCATE TABLE command is used to delete complete data from an existing table.
