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CRUD operations in SQL Server
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Cách tạo và sử dụng quy trình lưu trữ CRUD trong SQL Server
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Xem xét kỹ hơn các thủ tục được lưu trữ CRUD
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CRUD Operations in SQL – javatpoint
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- Summary of article content: Articles about CRUD Operations in SQL – javatpoint In CRUD operations, ‘C’ is an acronym for create, which means to add or insert data into the SQL table. So, firstly we will create a table using CREATE command … …
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How to Create Customizable CRUD Operations with SQL Complete – Devart Blog
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- Table of Contents:
Introduction
Generating the CRUD Procedures in SQL Complete
CREATE CRUD – Insert SQL Server Procedure
READ CRUD – Select SQL Server Procedure
UPDATE CRUD – Update SQL Server Procedure
DELETE CRUD – Delete SQL Server Procedure
Generating a CRUD Procedure
Conclusion
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What are SQL CRUD operations? | Codebots
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- Summary of article content: Articles about What are SQL CRUD operations? | Codebots All operations you can do on any data can be boiled down to Create, Read, Update, and Delete (CRUD). You can create something new, you can read … …
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[Thực hành] Thực thi các câu lệnh CRUD trên CSDL có sẵn – CodeGym
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CRUD Operations in MySQL – GeeksforGeeks
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CRUD operations explained: Create, read, update, delete
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CREATE
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CRUD operations in SQL Server
CRUD operations are foundation operations every database developer and administrator needs to understand. Let’s take a look at how they work with this guide.
Introduction
According to Wikipedia…
“In computer programming, create, read, update, and delete (CRUD) are the four basic functions of persistent storage. Alternate words are sometimes used when defining the four basic functions of CRUD, such as retrieve instead of read, modify instead of update, or destroy instead of delete. CRUD is also sometimes used to describe user interface conventions that facilitate viewing, searching, and changing information; often using computer-based forms and reports. The term was likely first popularized by James Martin in his 1983 book managing the Data-base Environment. The acronym may be extended to CRUDL to cover listing of large data sets which bring additional complexity such as pagination when the data sets are too large to hold easily in memory.”
CRUD is an acronym that stands for Create, Read, Update, and Delete.
These are the four most basic operations that can be performed with most traditional database systems and they are the backbone for interacting with any database.
Getting started
Let’s get started to understand the concepts of CRUD operations in SQL Server
Create
The first letter of CRUD, ‘C’, refers to CREATE aka add, insert. In this operation, it is expected to insert a new record using the SQL insert statement. SQL uses INSERT INTO statement to create new records within the table.
Let us create a simple table named Demo for this example.
1 2 3 4 5 6 7 USE AdventureWorks2016 ; GO DROP TABLE IF EXISTS Demo ; CREATE TABLE dbo . Demo ( id INT , name VARCHAR ( 100 ) ) ;
SQL Insert starts with the keyword INSERT INTO then specify the table name and the columns that we want to insert. The columns go inside of the parentheses and then we specify a VALUES clause.
1 2 3 INSERT INTO < tablename > ( column1 , column2 , … . ) VALUES ( value1 , value2 , … . )
We put in the table name demo after the insert into command. Now, supply the values to the listed columns id and name in the VALUES clause.
1 2 3 4 5 INSERT INTO dbo . Demo VALUES ( 1 , ‘Prashanth’ ) ;
To insert multiple rows, follow the below syntax
1 2 3 INSERT INTO < tablename > ( column1 , column2 , … . ) VALUES ( value1 , value2 , … . ) , ( value1 , value2 , … . ) , ( value1 , value2 , … . ) …
In the following example, the multiple values are listed within in the parenthesis and each list is separated by a comma delimiter
1 2 3 4 5 6 7 8 9 10 11 INSERT INTO dbo . Demo ( id , name ) VALUES ( 2 , ‘Jayaram’ ) , ( 3 , ‘Pravitha’ ) ;
To insert rows from SQL Union clause, follow the below syntax
1 2 3 4 INSERT INTO < tablename > ( column1 , column2 , … . ) SELECT value1 , value2 , … UNION ALL SELECT value1 , value2 , …
In the following example, the multiple values are listed using SELECT statement and then these values combined and fed to the table using SQL UNION ALL set operator.
1 2 3 4 5 6 INSERT INTO dbo . demo SELECT 4 , ‘Prarthana’ UNION ALL SELECT 5 , ‘Ambika’ ;
The output lists all the inserted rows from the above samples.
Notes: It is mandatory to insert at least all of the required columns, but you don’t have to update a column if those values are not required, or if there is a default value for that column A detailed explanation of SQL insert can be found in the following article: Overview of the SQL Insert statement SQL Insert statement only works against a single table unlike select which can work against multiple tables A detailed explanation of SQL Union clause can be found in the following article: SQL Union overview, usage and examples
Read
The second letter of CRUD , ‘R’, refers to SELECT (data retrieval) operation. The word ‘read’ retrieves data or record-set from a listed table(s). SQL uses the SELECT command to retrieve the data. When it comes to executing queries, you can use SQL Server Management Studio or SQL Server Data Tools or sqlcmd, based on your preference.
For example, to read related data from the specified table, refer to the below syntax.
1 SELECT * FROM < TableName >
The SQL select statement allows you to query the tables. It allows you to retrieve specific data, one or more rows from one or more tables.
The SQL SELECT statement in a vast majority of the time going to contain names of columns from the table(s) that you would like to get data from. Once you have column names, the table name is required in the FROM clause. Now, in a SELECT list, after every column of data, you’re going to need a comma. So you separate each column with a comma, except, no comma after the last column. We’re going to have the SELECT keyword, column name followed by a comma, column name, and the last column name, no comma, FROM clause followed by table name.
In this case, one that will return every row in the Address table. And it will return just the AddressID, AddressLine1,AddressLine2,City, StateProvinceID and PostalCode columns.
The SQL SELECT statement uses a wildcard character (*) or asterisk to populate all the columns of the table(s). It provides a way to not have to list every column table(s). That’s by using the asterisk or ‘*’.
The output lists all the columns of the Address table. The following SQL going to give me all of the columns
1 2 3 USE [ AdventureWorks2016 ] ; GO SELECT * FROM [ Person ] . [ Address ] ;
Next, the FROM Clause is going to have at least a table or it is possible to have multiple tables using SQL Join.
In the following example, the Product and SalesOrderDetail tables are listed in the FROM Clause of the Select statement.
1 2 3 SELECT * FROM Production . Product AS p JOIN Sales . SalesOrderDetail AS s ON s . ProductID = p . ProductID ;
Notes: A detailed explanation of a few more SQL SELECT statement scenarios is discussed in the article: Overview of the SQL Order by clause
Update
The third letter of CRUD, ‘U’, refers to Update operation. Using the Update keyword, SQL brings a change to an existing record(s) of the table.
You can refer to the article Overview of SQL Update to learn more about SQL update.
When performing an update, you’ll need to define the target table and the columns that need to update along with the associated values, and you may also need to know which rows need to be updated. In general, you want to limit the number of rows in order to avoid lock escalation and concurrency issues.
The basic syntax for an update:
1 2 3 UPDATE < TableName > SET Column1 = Value1 , Column2 = Value2 , … WHERE < Expression >
The UPDATE keyword is followed by the name of the table or view to be updated, and then the set keyword followed by the column name and the value to be set, be it an expression, default, keyword, or null value. If you’re looking to specify which rows are modified using a search condition, the syntax is as follows: Everything is the same as the previous example, only this time you’ll see the “where” clause followed by an expression.
A detailed explanation of SQL Update can be found in the following article: Overview of the SQL update statement
Delete
The last letter of the CRUD operation is ‘D’ and it refers to removing a record from a table. SQL uses the SQL DELETE command to delete the record(s) from the table.
You can refer to the article Overview of SQL Delete to learn more about SQL delete operation.
For example, to delete related data from the specified table, refer to the below syntax
1 2 DELETE FROM < TableName > WHERE < Expression >
When writing a DELETE statement, you’ll define the target table and also which rows you need to delete from the table. The syntax in its simplest form is the DELETE keyword followed by the table name. In some case without a WHERE clause in the query deletes ALL existing rows from the table. To apply a condition clause to the SQL DELETE statement, use the WHERE clause followed by the expression(s).
Note: The detailed explanation of SQL delete can be found in the following article: Overview of the SQL delete statement
Summary
So, thus far, we’ve discussed a lot about CRUD operations. It is a termed as the foundation of SQL operations in any database products. We also discussed how to implement CRUD Operations in SQL Server.
I would recommend reading SQL Insert, SQL Delete, and SQL Update articles which part of CRUD operations. Implementing the Create, Update, Delete, and insert operations are reasonably simple because they are very similar operations.
The most efficient way to implement CRUD operations in SQL is through stored procedures. You can refer to the article Creating and using CRUD stored procedures for further reading.
Thanks so much for taking the time to read this article. I hope you found it simple and valuable. Feel free leave the comment below.
Cách tạo và sử dụng quy trình lưu trữ CRUD trong SQL Server
Hầu hết các hệ thống cơ sở dữ liệu hoạt động trên cơ sở 4 trong số các thao tác thao tác dữ liệu đơn giản nhất được gọi bằng từ viết tắt CRUD. Từ viết tắt này là viết tắt của CREATE, READ, UPDATE và DELETE.
Khi phát triển và quản lý cơ sở dữ liệu, bạn có thể sử dụng các thủ tục được lưu trữ CRUD để thực hiện tất cả các tác vụ liên quan đến dữ liệu. Lợi ích của các thủ tục được lưu trữ như vậy là khi chúng được viết một lần, chúng có thể được sử dụng lại nhiều lần theo yêu cầu mà không cần phải viết mã mới mỗi lần. Đây là một cải tiến tuyệt vời so với các câu lệnh SQL đặc biệt nên được viết lại mỗi khi chúng ta sử dụng chúng.
Hãy xem xét chi tiết từng quy trình được lưu trữ CRUD.
Xem xét kỹ hơn các thủ tục được lưu trữ CRUD
Trước khi tiếp tục, có một điều chúng tôi muốn nói về việc đặt tên cho các thủ tục được lưu trữ CRUD. Thông thường, một phương pháp hay là đặt tên cho chúng theo cách mà mỗi thủ tục chứa tên của bảng mà chúng được áp dụng và cũng kết thúc bằng tên của thao tác mà chúng đang thực hiện. Bằng cách này, tất cả các thủ tục được viết cho cùng một bảng sẽ được nhóm lại với nhau và dễ dàng tìm kiếm hơn nhiều.
Tuy nhiên, nó không phải là bắt buộc và bạn có thể áp dụng bất kỳ mẫu đặt tên nào bạn thích.
Bây giờ, chúng ta hãy xem xét loại thủ tục đầu tiên.
Bạn cũng có thể muốn đọc: Bộ sưu tập: Cơ sở dữ liệu mẫu SQL Server
TẠO thủ tục
Chúng sẽ thực hiện một câu lệnh INSERT, tạo một bản ghi mới. Các thủ tục như vậy nên chấp nhận một tham số cho mỗi cột của bảng.
IF OBJECT_ID(‘Sales.usp_Currency_Insert’) IS NOT NULL BEGIN DROP PROC Sales.usp_Currency_Insert END GO CREATE PROC Sales.usp_Currency_Insert @CurrencyCode NCHAR(3), @Name dbo.Name, @ModifiedDate datetime AS SET NOCOUNT ON SET XACT_ABORT ON BEGIN TRAN INSERT INTO Sales.Currency (CurrencyCode, Name, ModifiedDate) SELECT @CurrencyCode, @Name, @ModifiedDate /* — Begin Return row code block SELECT CurrencyCode, Name, ModifiedDate FROM Sales.Currency WHERE CurrencyCode = @CurrencyCode AND Name = @Name AND ModifiedDate = @ModifiedDate — End Return row code block */ COMMIT GO
ĐỌC thủ tục
Thủ tục READ truy xuất các bản ghi bảng dựa trên khóa chính được cung cấp trong tham số đầu vào.
IF OBJECT_ID(‘Sales.usp_Currency_Select’) IS NOT NULL BEGIN DROP PROC Sales.usp_Currency_Select END GO CREATE PROC Sales.usp_Currency_Select @CurrencyCode NCHAR(3), @Name dbo.Name AS SET NOCOUNT ON SET XACT_ABORT ON BEGIN TRAN SELECT CurrencyCode, Name, ModifiedDate FROM Sales.Currency WHERE CurrencyCode = @CurrencyCode AND Name = @Name COMMIT GO
CẬP NHẬT thủ tục
Các thủ tục này sử dụng khóa chính cho một bản ghi được chỉ định trong mệnh đề WHERE để thực thi một câu lệnh UPDATE trên một bảng. Cũng giống như thủ tục CREATE, nó chấp nhận một tham số cho mỗi cột bảng.
IF OBJECT_ID(‘Sales.usp_Currency_Update’) IS NOT NULL BEGIN DROP PROC Sales.usp_Currency_Update END GO CREATE PROC Sales.usp_Currency_Update @CurrencyCode NCHAR(3), @Name dbo.Name, @ModifiedDate datetime AS SET NOCOUNT ON SET XACT_ABORT ON BEGIN TRAN UPDATE Sales.Currency SET ModifiedDate = @ModifiedDate WHERE CurrencyCode = @CurrencyCode AND Name = @Name /* — Begin Return row code block SELECT ModifiedDate FROM Sales.Currency WHERE CurrencyCode = @CurrencyCode AND Name = @Name — End Return row code block */ COMMIT GO
Thủ tục XÓA
Thủ tục này sẽ xóa một hàng được cung cấp trong mệnh đề WHERE của câu lệnh.
IF OBJECT_ID(‘Sales.usp_Currency_Delete’) IS NOT NULL BEGIN DROP PROC Sales.usp_Currency_Delete END GO CREATE PROC Sales.usp_Currency_Delete @CurrencyCode NCHAR(3), @Name dbo.Name AS SET NOCOUNT ON SET XACT_ABORT ON BEGIN TRAN DELETE FROM Sales.Currency WHERE CurrencyCode = @CurrencyCode AND Name = @Name COMMIT GO
Tạo thủ tục CRUD bằng dbForge SQL Complete
Sử dụng phần bổ trợ dbForge SQL Complete hoạt động cả trong SSMS và Visual Studio, chúng tôi có thể tạo thủ tục CRUD trong một vài cú nhấp chuột với nhiều tùy chọn cho phép định cấu hình cách tạo chính xác các thủ tục này. Trong bài viết này, chúng tôi sẽ sử dụng SSMS để hiển thị chức năng của SQL Complete.
Để tạo quy trình CRUD cho một bảng, hãy bấm chuột phải vào bảng, đi tới menu Hoàn thành SQL và bấm Bảng Tập lệnh dưới dạng CRUD:
Khi điều này được thực hiện, một tệp SQL mới sẽ được mở. Tại đây, bạn có thể xem tất cả các hoạt động CRUD cho bảng.
Thay đổi cài đặt tạo CRUD
Để định cấu hình cách dbForge SQL Complete tạo CRUD, trước tiên bạn cần đi tới menu Hoàn thành SQL ở đầu cửa sổ và nhấp vào Tùy chọn:
Kết quả là trong cửa sổ Tùy chọn sẽ được mở ra, hãy chuyển đến menu CRUD và nhấp vào Chung:
Trong tab này, bạn có thể chỉ định thủ tục nào bao gồm trong quá trình tạo CRUD và chỉ định thứ tự cột nào để sử dụng – theo thứ tự bảng chữ cái hoặc theo số thứ tự.
Bạn cũng có thể định cấu hình từng quy trình riêng biệt bằng cách chọn tùy chọn tương ứng trong menu CRUD. Trước hết, bạn có thể thay đổi tên của các thủ tục đã tạo theo cách thủ công:
Tiếp theo, có các tùy chọn duy nhất cho mỗi thủ tục.
Đối với SELECT, có một hộp kiểm Trả về tất cả dữ liệu nếu các tham số đầu vào là rỗng
Đối với INSERT, bạn có thể chỉ định xem có trả lại hàng đã chèn sau khi hoàn thành hay không
Tùy chọn tương tự có sẵn cho UPDATE – nó cho phép bạn chọn xem bạn có muốn trả lại hàng đã cập nhật hay không.
Không có tùy chọn duy nhất bổ sung cho XÓA.
Cuối cùng, đối với mỗi thủ tục, có phần Mẫu mã. Trong phần này, bạn có thể thay đổi cách tạo mã của thủ tục được chỉ định. Trong các mẫu mã, có các tham số được cung cấp ở định dạng $ name $ (ví dụ: $ schema $ hoặc $ column $). Bằng cách thay đổi các tham số này, bạn có thể sửa đổi mã của thủ tục đã tạo.
Phần kết luận
Như bạn có thể thấy, việc triển khai và quản lý quá trình thao tác dữ liệu bằng cách sử dụng các lệnh CRUD sẽ thích hơn nhiều so với việc sử dụng các câu lệnh SQL đặc biệt. Điều này có thể được thực hiện dễ dàng với sự trợ giúp của phần bổ trợ dbForge SQL Complete. Tuy nhiên, làm việc với CRUD không phải là chức năng duy nhất của nó (và trong một thời gian dài).
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CRUD Operations in SQL
CRUD Operations in SQL
As we know, CRUD operations act as the foundation of any computer programming language or technology. So before taking a deeper dive into any programming language or technology, one must be proficient in working on its CRUD operations. This same rule applies to databases as well.
Let us start with the understanding of CRUD operations in SQL with the help of examples. We will be writing all the queries in the supporting examples using the MySQL database.
1. Create:
In CRUD operations, ‘C’ is an acronym for create, which means to add or insert data into the SQL table. So, firstly we will create a table using CREATE command and then we will use the INSERT INTO command to insert rows in the created table.
Syntax for table creation:
CREATE TABLE Table_Name (ColumnName1 Datatype, ColumnName2 Datatype,…, ColumnNameN Datatype);
where,
Table_Name is the name that we want to assign to the table.
Column_Name is the attributes under which we want to store data of the table.
Datatype is assigned to each column. Datatype decides the type of data that will be stored in the respective column.
Syntax for insertion of data in table:
INSERT INTO Table_Name (ColumnName1,…., ColumnNameN) VALUES (Value 1,….,Value N),….., (Value 1,….,Value N);
Prior to the creation of a table in SQL, we need to create a database or select an existing database. Since we already had a database, we will select the database with the USE command.
mysql> USE dbe;
Now, we will write a query to create a table named employee in the database named dbe.
mysql> CREATE TABLE employee(ID INT PRIMARY KEY, First_Name VARCHAR(20), Last_Name VARCHAR(20), Salary INT, Email_Id VARCHAR(40));
To ensure that the table is created as per the column names, data types and sizes which we have assigned during table creation, we will execute the following query:
mysql> DESC employee;
You will get the following output:
Field Type Null Key Default Extra ID int(11) NO PRI NULL First_Name varchar(20) YES NULL Last_Name varchar(20) YES NULL Salary int(11) YES NULL Email_Id varchar(40) YES NULL
The above results verify that the table is created successfully as per the requirements.
We will execute the following query to insert multiple records in the employee table:
INSERT INTO employee(ID, First_Name, Last_Name, Salary, Email_Id) VALUES(1, “Neeta”, “Korade”, 59000, “[email protected]”), (2, “Sushma”, “Singh”, 62000, “[email protected]”), (3, “Kavita”, “Rathod”, 27000, “[email protected]”), (4, “Mrunalini”, “Deshmukh”, 88000, “[email protected]”), (5, “Swati”, “Patel”, 34000, “[email protected]”), (6, “Laxmi”, “Kadam”, 44000, “[email protected]”), (7, “Lalita”, “Shah”, 66000, “[email protected]”), (8, “Savita”, “Kulkarni”, 31000, “[email protected]”), (9, “Shravani”, “Jaiswal”, 38000, “[email protected]”), (10, “Shweta”, “Wagh”, 20000, “[email protected]”);
2. Read:
In CRUD operations, ‘R’ is an acronym for read, which means retrieving or fetching the data from the SQL table. So, we will use the SELECT command to fetch the inserted records from the SQL table. We can retrieve all the records from a table using an asterisk (*) in a SELECT query. There is also an option of retrieving only those records which satisfy a particular condition by using the WHERE clause in a SELECT query.
Syntax to fetch all the records:
SELECT *FROM TableName;
Syntax to fetch records according to the condition:
SELECT *FROM TableName WHERE CONDITION;
Example 1:
Write a query to fetch all the records stored in the employee table.
Query:
mysql> SELECT *FROM employee;
Here, an asterisk is used in a SELECT query. This means all the column values for every record will be retrieved.
You will get the following output after executing the above query:
All the records are successfully retrieved from the employee table.
Example 2:
Write a query to fetch only those records from the employee table whose salary is above 35000.
Query:
mysql> SELECT *FROM employee WHERE Salary > 35000;
Here, an asterisk is used in a SELECT query. This means all the column values for every record will be retrieved. We have applied the WHERE clause on Salary, which means the records will be filtered based on salary.
You will get the output as follows:
There are six records in the employee table whose salary is above 35000.
3. Update:
In CRUD operations, ‘U’ is an acronym for the update, which means making updates to the records present in the SQL tables. So, we will use the UPDATE command to make changes in the data present in tables.
Syntax:
UPDATE Table_Name SET ColumnName = Value WHERE CONDITION;
Example 1:
Write a query to update an employee’s last name as ‘Bose’, whose employee id is 6.
Query:
mysql> UPDATE employee SET Last_Name = “Bose” WHERE ID = 6;
Here in the SELECT query, we have used the SET keyword to update an employee’s last name as ‘Bose’. We want to update an employee’s last name only for the employee with id 6, so we have specified this condition using the WHERE clause.
To ensure that an employee’s last name with employee id 6 is updated successfully, we will execute the SELECT query.
mysql> SELECT *FROM employee;
The results above verify that an employee’s last name with employee id 6 is now changed to ‘Bose’.
Example 2:
Write a query to update the salary and email id of an employee as ‘35000’ and ‘[email protected]’, respectively, whose employee id is 10.
Query:
mysql> UPDATE employee SET Salary = “35000”, Email_Id= “[email protected]” WHERE ID = 10;
Here in the UPDATE query, we have used the SET keyword to update an employee’s salary as ‘35000’ and the email id as ‘[email protected]’. We want to update the salary and email id of an employee only for the employee with id 10, so we have specified this condition using the WHERE clause.
To ensure that the salary and email id of an employee with employee id 10 is updated successfully, we will execute the SELECT query.
mysql> SELECT *FROM employee;
The results above verify that the salary and email id of an employee with employee id 10 is now changed to ‘35000’ and ‘[email protected]’, respectively.
4. Delete:
In CRUD operations, ‘D’ is an acronym for delete, which means removing or deleting the records from the SQL tables. We can delete all the rows from the SQL tables using the DELETE query. There is also an option to remove only the specific records that satisfy a particular condition by using the WHERE clause in a DELETE query.
Syntax to delete all the records:
DELETE FROM TableName;
Syntax to delete records according to the condition:
DELETE FROM TableName WHERE CONDITION;
Example 1:
Write a query to delete the employee record from the employee table whose salary is above 34000.
Query:
mysql> DELETE FROM employee WHERE Salary = 34000;
Here we have applied the DELETE query on the employee table. We want to delete only the employee record whose salary is 34000, so we have specified this condition using the WHERE clause.
We will execute the SELECT query to ensure that the employee record with salary as 34000 is deleted successfully.
mysql> SELECT *FROM employee;
The results above verify that the employee with a salary of 34000 no longer exists in the employee table.
Example 2:
Write a query to delete all the records from the employee table.
First, let us see the employee table, which is available currently.
mysql> SELECT *FROM employee;
To remove all the records from the employee table, we will execute the DELETE query on the employee table.
mysql> DELETE FROM employee;
We will execute the SELECT query to ensure that all the records are deleted successfully from the employee table.
mysql> SELECT *FROM employee;
The results above verify that the employee table does not contain any record now.
So you have finished reading the crud sql topic article, if you find this article useful, please share it. Thank you very much. See more: CRUD, CRUD operation, CRUD MySQL, CRUD stands for, Delete in crud operation, CRUD query in SQL, What is CRUD, CRUD stored procedure