Ring/Lessons/MySQL Functions
MySQL Functions edit
In this chapter we are going to learn about the MySQL functions provided by the Ring programming language. Before using the functions load the mysqllib.ring library:
load "mysqllib.ring"
- MySQL_Info()
- MySQL_Init()
- MySQL_Error()
- MySQL_Connect()
- MySQL_Close()
- MySQL_Query()
- MySQL_Insert_ID()
- MySQL_Result()
- MySQL_Next_Result()
- MySQL_Columns()
- MySQL_Result2()
- MySQL_Escape_String()
- MySQL_AutoCommit()
- MySQL_Commit()
- MySQL_Rollback()
MySQL_Info() Function edit
We can get the MySQL Client version using the MySQL_Info() function.
Syntax:
MySQL_Info() ---> string contains the MySQL Client version
Example:
see "MySQL Client Version : " + mysql_info()
Output:
MySQL Client Version : 6.1.5
MySQL_Init() Function edit
We can start using MySQL Client through the MySQL_Init() function.
Syntax:
MySQL_Init() ---> MySQL Handle
MySQL_Error() Function edit
We can get the error message from the MySQL Client using the MySQL_Error() function.
Syntax:
MySQL_Error(MySQL Handle) ---> Error message as string
MySQL_Connect() Function edit
We can connect to the MySQL database server using the MySQL_Connect() function.
Syntax:
MySQL_Connect(MySQL Handle, cServer, cUserName, cPassword) ---> lStatus
MySQL_Close() Function edit
We can close the connection to the MySQL database using the MySQL_Close() function
Syntax:
MySQL_Close(MySQL Handle)
MySQL_Query() Function edit
We can execute SQL queries using the MySQL_Query() function
Syntax:
MySQL_Query(MySQL Handle, cSQLQuery)
Create Database edit
The next example connect to MySQL Server then create new database.
See "MySQL Test - Create Database" + nl
con = mysql_init()
See "Connect" + nl
if mysql_connect(con,"localhost","root","root") = 0
see "Cann't connect" + nl
see "Error : " + mysql_error(con) + nl
mysql_close(con)
bye
ok
See "Create Database..." + nl
mysql_query(con,"CREATE DATABASE mahdb")
See "Close Connection" + nl
mysql_close(con)
Output:
MySQL Test - Create Database
Connect
Create Database...
Close Connection
Create Table and Insert Data edit
The next example create new table and insert records
func main
see "Create Table and Insert Records" + nl
con = mysql_init()
see "Connect" + nl
if mysql_connect(con, "localhost", "root", "root","mahdb") = 0
system_error(con)
ok
see "Drop table" + nl
if mysql_query(con, "DROP TABLE IF EXISTS Employee") system_error(con) ok
see "Create table" + nl
if mysql_query(con, "CREATE TABLE Employee(Id INT, Name TEXT, Salary INT)")
system_error(con) ok
see "Insert data" + nl
if mysql_query(con, "INSERT INTO Employee VALUES(1,'Mahmoud',15000)")
system_error(con) ok
if mysql_query(con, "INSERT INTO Employee VALUES(2,'Samir',16000)")
system_error(con) ok
if mysql_query(con, "INSERT INTO Employee VALUES(3,'Fayed',17000)")
system_error(con) ok
see "Close connection" + nl
mysql_close(con)
func system_error con
see mysql_error(con) mysql_close(con) bye
Output:
Create Table and Insert Records
Connect
Drop table
Create table
Insert data
Close connection
MySQL_Insert_ID() Function edit
We can get the inserted row id using the MySQL_Insert_ID() function
Syntax:
MySQL_Insert_ID() ---> Inserted row id as number
Example:
con = mysql_init()
see "connect to database" + nl
mysql_connect(con,"localhost","root","root","mahdb")
see "drop table" + nl
mysql_query(con, "DROP TABLE IF EXISTS Customers")
see "create table" + nl
mysql_query(con, "CREATE TABLE Customers(Id INT PRIMARY KEY AUTO_INCREMENT, Name TEXT)")
see "insert record" + nl
mysql_query(con, "INSERT INTO Customers(Name) VALUES('Mahmoud')")
see "insert record" + nl
mysql_query(con, "INSERT INTO Customers(Name) VALUES('Samir')")
see "insert record" + nl
mysql_query(con, "INSERT INTO Customers(Name) VALUES('Fayed')")
see "insert record" + nl
mysql_query(con, "INSERT INTO Customers(Name) VALUES('Test 2015')")
see "inserted row id : " + mysql_insert_id(con) + nl see "close database" + nl mysql_close(con)
Output:
connect to database
drop table
create table
insert record
insert record
insert record
insert record
inserted row id : 4
close database
MySQL_Result() Function edit
We can get the query result (data without column names) using the MySQL_Result() function.
Syntax:
MySQL_Result(MySQL Handle) ---> List contains the query result
MySQL_Next_Result() Function edit
We can move to the next query result using the MySQL_Next_Result() function. We use this function when we have multiple SQL statements in the same query.
Syntax:
MySQL_Next_Result(MySQL Handle)
Print Query Result edit
The next example execute a query on the database then print the result.
con = mysql_init()
see "Connect to database" + nl
mysql_connect(con, "localhost", "root", "root","mahdb")
see "Execute Query" + nl
mysql_query(con, "SELECT Name FROM Employee WHERE Id=1;"+
"SELECT Name FROM Employee WHERE Id=3")
see "Print Result" + nl
see mysql_result(con)
mysql_next_result(con)
see mysql_result(con)
see "close database" + nl
mysql_close(con)
Output:
Connect to database
Execute Query
Print Result
Mahmoud
Fayed
close database
MySQL_Columns() Function edit
We can get a list of columns names using the MySQL_Columns() function.
Syntax:
MySQL_Columns(MySQL Handle) ---> List contains columns information
Example:
con = mysql_init()
see "Connect to database" + nl
mysql_connect(con, "localhost", "root", "root","mahdb")
see "Execute Query" + nl
mysql_query(con, "SELECT * FROM Employee")
see "Result" + nl
see mysql_columns(con)
see "Close database" + nl
mysql_close(con)
Output:
Connect to database
Execute Query
Result
Id
11
3
32768
Name
65535
252
16
Salary
11
3
32768
Close database
MySQL_Result2() Function edit
Instead of using MySQL_Result() to get the result data without columns names, we can use the MySQL_Result2() to get all of the column names then the query result in one list.
Syntax:
MySQL_Result2(MySQL Handle) ---> List (query result starts with columns names)
Example:
con = mysql_init()
see "Connect to database" + nl
mysql_connect(con, "localhost", "root", "root","mahdb")
see "Execute Query" + nl
mysql_query(con, "SELECT * FROM Employee")
see "Print Result" + nl
see mysql_result2(con)
see "Close database" + nl
mysql_close(con)
Output:
Connect to database
Execute Query
Print Result
Id
Name
Salary
1
Mahmoud
15000
2
Samir
16000
3
Fayed
17000
Close database
MySQL_Escape_String() Function edit
We can store binary data and special characters in the database after processing using MySQL_Escape_String() function
Syntax:
MySQL_Escape_String(MySQL Handle, cString) ---> String after processing
Save Image inside the database edit
Example:
See "Read file" + nl
cFile = read("tests\mahmoud.jpg")
con = mysql_init()
See "Connect to database..." + nl
mysql_connect(con, "localhost", "root", "root","mahdb")
See "Escape string..." + nl
cFile = mysql_escape_string(con,cFile)
stmt = "INSERT INTO photo(id, data) VALUES(1, '" + cFile + "')"
See "Insert data..." + nl
mysql_query(con,stmt)
See "Close database..." + nl
mysql_close(con)
Output:
Read file
Connect to database...
Escape string...
Insert data...
Close database...
Restore Image From The Database edit
Example:
con = mysql_init()
See "Connect to database..." + nl
mysql_connect(con, "localhost", "root", "root","mahdb")
See "Read data from database..." + nl
mysql_query(con,"SELECT data FROM photo WHERE id=1")
See "Write new file" + nl
result = mysql_result(con)
write("tests\mahmoud2.jpg",result[1][1])
See "Close database..." + nl
mysql_close(con)
Output:
Connect to database...
Read data from database...
Write new file
Close database...
MySQL_AutoCommit() Function edit
We can enable or disable the auto commit feature using the MySQL_AutoCommit() function.
Syntax:
MySQL_AutoCommit(MySQL Handle, lStatus) # lstatus can be True/False
MySQL_Commit() Function edit
We can commit updates to the database using the MySQL_Commit() function.
Syntax:
MySQL_Commit(MySQL Handle)
MySQL_Rollback() Function edit
We can rollback updates to the database using the MySQL_Rollback() function.
Syntax:
MySQL_Rollback(MySQL Handle)
Transaction Example edit
The next example presents the usage of MySQL_Autocommit(), MySQL_Commit() & MySQL_RollBack() functions.
Example:
func main
con = mysql_init()
see "Connect" + nl
if mysql_connect(con, "localhost", "root", "root","mahdb") = 0
system_error(con) ok
see "Drop table" + nl
if mysql_query(con, "DROP TABLE IF EXISTS Employee2")
system_error(con) ok
see "Create table" + nl
if mysql_query(con, "CREATE TABLE Employee2(Id INT, Name TEXT, Salary INT)")
system_error(con) ok
see "Insert data" + nl
if mysql_query(con, "INSERT INTO Employee2 VALUES(1,'Mahmoud',15000)")
system_error(con) ok
if mysql_query(con, "INSERT INTO Employee2 VALUES(2,'Samir',16000)")
system_error(con) ok
if mysql_query(con, "INSERT INTO Employee2 VALUES(3,'Fayed',17000)")
system_error(con) ok
mysql_autocommit(con,False)
mysql_query(con, "INSERT INTO Employee2 VALUES(4,'Ahmed',5000)")
mysql_query(con, "INSERT INTO Employee2 VALUES(5,'Ibrahim',50000)")
mysql_query(con, "INSERT INTO Employee2 VALUES(6,'Mohammed',50000)")
See "Save transaction (y/n) " give nChoice
if upper(nChoice) = "Y"
mysql_commit(con)
else
mysql_rollback(con)
ok
see "Close connection" + nl
mysql_close(con)
func system_error con
see mysql_error(con)
mysql_close(con)
bye
Output:
Connect
Drop table
Create table
Insert data
Save transaction (y/n) y
Close connection