➤ EMP DEPT Tables Queries
➤ Set Operators in Oracle
➤ CREATE command
➤ RENAME command
➤ DROP command
➤ Default Value in Column
➤ ABS() in Oracle SQL
➤ CEIL() in Oracle SQL
➤ SYSDATE in Oracle
➤ Trunc Oracle date
➤ TO_CHAR() in Oracle
➤ GROUP BY Clause
➤ Having Clause
➤ ORDER BY Clause
➤ Constraints in Oracle
➤ Rename Constraint
➤ Disable Constraint
➤ Drop Constraint
➤ NOT NULL Constraint
➤ UNIQUE Constraint
➤ PRIMARY KEY Constraint
➤ FOREIGN KEY Constraint
➤ CHECK Constraint
➤ Unlock User in SQL Plus
➤ Find SID in Oracle database
➤ Check Database Version
➤ Check Database Size
➤ Error ORA 01031
Oracle Drop Table If Exists And Create | In this post, we will see how to drop the table if the table exists and after dropping the table how to create the table.
What is Drop?
Drop in the oracle is used to remove or delete the tables in the oracle. Using Drop we can delete a single table or multiple tables based on the condition.
Syntax of Drop:-
DROP [schemaname].TABLE tablename [CASCADE CONSTRAINTS] [PURGE];
Cascade constraints are optional, if it is specified it will drop all the referential integrity constraints. Purge is also optional, if it is specified then the table and all its dependable objects are removed and it cannot be recovered from the recycle bin.
Let’s see how to drop the table if it exists, if it doesn’t exist then we will create. Here we are using the stored procedure to execute the above condition specified.
Let’s create a sample table “test”, and insert some data into it.
CREATE TABLE test(id int, name VARCHAR(20)); INSERT INTO test VALUES(1, 'John'); INSERT INTO test VALUES(1, 'William'); SELECT * FROM test;
By using the DESC we will check the description of the table.
Name Null? Type -------- -------- ------------- ID NUMBER NAME VARCHAR2(20)
Now we have created the table “test”, we will execute the query to check if the table exists and drop the table and create it.
BEGIN BEGIN EXECUTE IMMEDIATE 'DROP TABLE test'; EXCEPTION WHEN OTHERS THEN IF SQLCODE != -942 THEN RAISE; END IF; END; EXECUTE IMMEDIATE 'CREATE TABLE test( id NUMBER, name VARCHAR(20), email VARCHAR(10) )'; END; /
PL/SQL procedure successfully completed.
Now let us see the description of the table to check if the table is created.
Name Null? Type -------- -------- ------------- ID NUMBER NAME VARCHAR2(20) EMAIL VARCHAR2(10)
From the above output, we can say that it has dropped the existing table and created a table, we can also check this by following the query.
SELECT * FROM test;
no rows selected
As the table is newly created and no data inserted we will get this output. This is how we drop the existing table and create the table in Oracle.
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