1. Create a new table, business_copy, and copy the data from the Bisiness table
CREATE TABLE business_copy
As
SELECT * from business;
NOTE: This SQL statement simply creates the table and replicates the table's data, but does not copy the constraints of the table.
2. Delete the table in PL/SQL developer
For example, delete a table business, perform a operation,
1) DROP TABLE business;
2) Locate this table, right-click and select Cross-boundary delete operation.
3. Quickly create a table in PL/SQL developer.
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4. How to quickly import data from a table into a new table.
INSERT into Business (busino,businame,itemno,starttime)
SELECT * FROM Business_copy
5. Store the document in the table;
1) Add a column with the name Busidoc, format blob, and add something to it
6. More commonly used field data types
Number (P,s): numeric type, p minimum is 1, maximum 38,s min-84, maximum 124;
Date: Day type, used to record time
char (size): Fixed length string type, compare the value of a field, know the specified length, can save a lot of space, speed up access
VARCHAR2 (size): variable long string type, more commonly used, such as the length of a person's name, you can give the maximum value
Blob: (Binary large objects, binary large object type) for storing binary objects, such as photos, document materials, etc.
CLOB: Large Object data (character large object character big data type) that stores characters, such as resumes
bfile: (binary file, binary files) stores large objects, such as film film, etc.
7. Modify the table structure in PL/SQL developer
1) Create a new SQL window and enter the SQL statement
ALTER TABLE ITEMS ADD (MANAGER VARCHAR2 (6)); Perform
Explanation: Alter is a frequently used keyword in the Oracle database, changing database parameters, table structure, etc. are used to
Eg: change manager input characters: Alter TABLE ITEMS Modify (Manager VARCHAR2 (8));
Add: Adds a list of keywords here
2) Modify data: Update items set manager= ' Ouyang unbeaten ' where itemname = ' Beijing project ';
3) Modify the maximum value of the table field: ALTER table ITEMS Modify (MANAGER VARCHAR2 (8));
4) Change the data in the table:
UPDATE items SET MANAGER = ' Ouyang unbeaten ' WHERE itemname = ' Shenzhen project ';
5) Delete a column of the table: ALTER table ITEMS DROP column MANAGER;
Copy table data to another table with PL/SQL developer