About Oracle DataBase

1. Introduction to relational database

The basic concept of relational data (relational database) is very simple to understand. A relational database is a set of related information that has already been organized into a table structure. Each table contains many rows, which are further organized into columns. These tables are stored in the schema (schema) in the database. A pattern is where a database user can store a table. Each user can grant access to their own tables for other users.

2, Structured Query Language SQL introduction

SQL is a standard language designed to access relational data. SQL statements can be divided into 5 categories

• Query statements are used to retrieve rows stored in a database table. Query statements can be written using the SQL SELECT statement

• Data manipulation language (manipulation LANGUAGE,DML) statement is used to modify the contents of the table, that is, additions and deletions

• The Data definition language (LANGUAGE,DDL) statement is used to define the data structure that constitutes the data, for example:

  • Create creates a table with a data table structure. Create user creates database users

  • Alter modifies the table structure by altering the table statement to alter

  • Drop Delete data table structure DROP TABLE statement is used to delete a sheet

  • RENAME changes indicate

  • TRUNCATE Delete all contents of a table

• A transaction control (Transaction CONTROLLER,TC) statement that stores all modifications to a row permanently in a table, or cancels the operation of those rows.

  • COMMIT to permanently save changes to the row

  • ROLLBACK canceling changes to a row

  • SavePoint setting a savepoint, you can change the operation of the row to roll back here

• Data Control Language (LANGUAGE,DCL) statements are used to modify the operation permissions of the database structure

  • Grant grants other users access to the database structure

  • REVOKE prevent other users from accessing the database structure

3. Using Sql*plus

Using the command line: Sqlplus [user_name/password[@host_string]]

User_name: User name password: login password host_string Specify connected database

After starting Sqlpuls, you can edit the last SQL statement of Sql*plus by entering the edit command

4. SQL devleloper, using graphical tools

5. Create store mode

5.1 Start Sql*plus and log in to the database with the Create new user, table, and PL/SQL packages. Run the Store.sql script with the @ command

5.2 DDL statements to create the store mode

Creating username: Create user user_name identified by password;

Give this user permission: GRANT connect,resource to user_name;

6. Add, modify, delete rows

The INSERT statement is used to add rows to the table, INSERT INTO table_name (COLUMN1,COLUMN2,... ) VALUES (value1,value2,...);

The UPDATE statement is used to modify existing rows in the table. UPDATE table_name SET column1 = Value1,column2 = value2,... WHERE table_pk = pk_id;

The DELETE statement is used to delete rows from the table. A where statement is generally used to limit the rows that you want to delete. Without throttling, all rows in the table are deleted. DELETE from table_name WHERE TABLE_PK = pk_id;

7. Advantages of Binary_float and binary_double data types

The required storage space is smaller binary_float and binary_double require 5 bytes and 9 bytes of storage space, while number may require 22 bytes of storage space

can represent a larger range of numbers

Perform operations faster. Binary is typically executed in hardware, so faster
Operation closure

Rounding transparent binary uses the binary to represent numbers, while number is represented by 10 binary.

8. Introduction to Oracle PL/SQL

PL/SQL is a process language for Oracle that can be used to add some SQL-based programming constructs. PL/SQL is primarily used to add procedures and functions to the database to implement business logic.

PL/SQL contains standard programming constructs such as variable declarations, conditional control (if-then-else), loops, procedures, and function definitions.

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About Oracle DataBase