Explore the basic knowledge and applications of Oracle transactions and stored procedures

Oracle is a database management system that uses transactions and stored procedures. In Oracle, a transaction refers to a series of operations performed on the database, all of which succeed or all of which fail. A stored procedure is a set of pre-written SQL statements that can be saved in the database in advance and then executed by calling it by name. This article will focus on the basic knowledge and applications of Oracle transactions and stored procedures.

1. Basic knowledge of transactions

In Oracle, a transaction consists of a series of operations on the database. These operations can be inserting, updating or deleting data, etc. Transactions must follow the ACID principle:

• Atomicity: Transactions must be atomic, either all succeed or all fail. If one part of the transaction fails, all operations performed must be undone.
• Consistency: The database must maintain consistency before and after transaction execution. This means that the database must meet its integrity rules before and after a transaction is executed.
• Isolation: Multiple transactions can perform operations on the database at the same time, but each transaction must have an independent space and will not affect other transactions. This prevents issues with concurrent access.
• Durability (Durability): Once the transaction is successfully submitted, the modifications to the database must be permanently saved and will not be lost even if the system fails.

2. Implementation of Oracle transactions

The implementation of Oracle transactions is completed by a mechanism called Undo Log. This mechanism records information related to the transaction so that it can be undone when necessary. When a transaction commits, the database will use these undo logs to ensure ACID principles.

In Oracle, a transaction is started and ended by the following statement:

BEGIN TRANSACTION;
-- Transaction operation
COMMIT;

If transaction If you need to abort, you can use the ROLLBACK statement:

ROLLBACK;

When using BEGIN TRANSACTION, Oracle will start a new transaction, and all operations will be performed in this transaction. The COMMIT statement commits the transaction, making the changes to the database permanent. The ROLLBACK statement undoes all changes to the database and terminates the current transaction.

3. Basic knowledge of stored procedures

In Oracle, a stored procedure is a set of pre-written SQL statements that can be saved in the database in advance and then called by name implement. Stored procedures can be executed independently and can have their own parameters and return values. Stored procedures are often used to perform complex operations such as data analysis and validation.

The syntax of a stored procedure is similar to the following example:

CREATE PROCEDURE ProcedureName
( [Parameter1 DataType] [= DefaultValue] [, [Parameter2 DataType] [= DefaultValue]] … )
[AS]
BEGIN
-- Operation of stored procedure
END;

Example of stored procedure:

CREATE PROCEDURE GetCustomerSales
(
IN customerID INT,
OUT totalSales DECIMAL(10,2)
)
AS
BEGIN
SELECT SUM(SalesAmount) INTO totalSales FROM Sales WHERE CustomerID = customerID;
END;

This stored procedure is named GetCustomerSales, which has an input parameter customerID and an output parameter totalSales. It will look up the total sales for a specific customer in the Sales table and store the result in the totalSales parameter.

4. Application of stored procedures

Stored procedures are widely used in Oracle database applications. Through stored procedures, complex business logic and data processing operations can be implemented. The following are some typical applications of stored procedures:

• Data processing and entry: Stored procedures can be used to process large amounts of data, such as batch inserting or updating data.
• Data conversion: Stored procedures can be used to convert data from one storage format to another.
• Data analysis and reporting: Stored procedures can be used to generate various types of reports and analyze data.
• Data validation: Stored procedures can be used to verify the validity of data, such as ensuring that the data conforms to a specific specification or format.

In short, Oracle transactions and stored procedures are very powerful tools that can be used to implement complex business logic and data processing operations. By using them effectively, the efficiency and reliability of data processing and management can be improved.

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