The Ring programming language version 1.5.3 book - Part 27 of 184
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This document discusses Ring's ODBC functions for connecting to databases. It describes functions for initializing an ODBC connection, getting lists of ODBC drivers and data sources, connecting to and executing queries on a data source, and closing an ODBC connection. Examples are given to print lists of available ODBC drivers and data sources on a system.
![Ring Documentation, Release 1.5.3
34.2 Main Menu
Example:
# Demo Program
while true
see "
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
" give nMenu see nl
# we can use Switch-ON-Other-OFF instead of IF-BUT-ELSE-OK
Switch nMenu
On 1 sayhello()
On 2 Sum()
On 3 Stars()
On 4
see "Enter Number : " give x
see "Output : "
Try
see Fact(number(x))
Catch
see "Error in parameters!" + nl
Done
On "5" return
Other see "bad option" + nl
Off
end
func sayhello
see "Enter your name ? " give fname
see "Hello " + fname + nl
func sum
see "number 1 : " give num1 see "number 2 : " give num2
see "Sum : " see 0 + num1 + num2
func stars
for x = 1 to 10
see space(8)
for y = 1 to x see "*" next see nl
next
func fact x if x = 0 return 1 else return x * fact(x-1) ok
34.2. Main Menu 239](https://image.slidesharecdn.com/261fayedringdoc1-180327101419/85/The-Ring-programming-language-version-1-5-3-book-Part-27-of-184-5-320.jpg)
![Ring Documentation, Release 1.5.3
func space x y = "" for t=1 to x y += " " next return y
Output:
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
1
Enter your name ? Mahmoud Fayed
Hello Mahmoud Fayed
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
2
number 1 : 3
number 2 : 4
Sum : 7
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
3
*
**
***
****
*****
******
*******
********
*********
**********
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
34.2. Main Menu 240](https://image.slidesharecdn.com/261fayedringdoc1-180327101419/85/The-Ring-programming-language-version-1-5-3-book-Part-27-of-184-6-320.jpg)
![Ring Documentation, Release 1.5.3
[3] Stars
[4] Fact
[5] Exit
4
Enter Number : 5
Output : 120
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
5
34.2. Main Menu 241](https://image.slidesharecdn.com/261fayedringdoc1-180327101419/85/The-Ring-programming-language-version-1-5-3-book-Part-27-of-184-7-320.jpg)
The Ring programming language version 1.5.3 book - Part 27 of 184
- 1. CHAPTER THIRTYTHREE EVAL() AND DEBUGGING In this chapter we are going to learn about • Error Handling using Try/Catch/Done • Eval() function • Raise() function • Assert() function 33.1 Try/Catch/Done Syntax: Try Statements... Catch Statements... Done The statements in the Try block will be executed, if any error happens then the statements in the catch block will be executed. Inside the catch block we can use the variable cCatchError to get the error message Example: Try see 5/0 Catch see "Catch!" + nl + cCatchError Done Output: Catch! Error (R1) : Cann't divide by zero ! 33.2 Eval() Function We can execute code during the runtime from string using the Eval() function Syntax: 235
- 2. Ring Documentation, Release 1.5.3 Eval(cCode) Example: Eval("nOutput = 5+2*5 " ) See "5+2*5 = " + nOutput + nl Eval("for x = 1 to 10 see x + nl next") Eval("func test see 'message from test!' ") test() Output: 5+2*5 = 15 1 2 3 4 5 6 7 8 9 10 message from test! 33.3 Raise() Function We can raise an exception using the Raise() function Syntax: Raise(cErrorMessage) The function will display the error message then end the execution of the program. We can use Try/Catch/Done to avoid exceptions generated by raise() function. Example: nMode = 10 if nMode < 0 or nMode > 5 raise("Error : nMode not in the range 1:4") ok Output: Line 4 Error : nMode not in the range 1:4 In raise in file testsraise.ring Example: try testmode(6) catch see "avoid raise!" done testmode(-1) 33.3. Raise() Function 236
- 3. Ring Documentation, Release 1.5.3 func testmode nMode if nMode < 0 or nMode > 5 raise("Error : nMode not in the range 1:4") ok Output: avoid raise! Line 12 Error : nMode not in the range 1:4 In raise In function testmode() in file testsraise2.ring called from line 7 in file testsraise2.ring 33.4 Assert() Function We can use the Assert() function to test conditions before executing the code If the test fail the program will be terminated with an error message contains the assert condition. Syntax: Assert( condition ) Example: x = 10 assert( x = 10) assert( x = 100 ) Output: Line 3 Assertion Failed! In assert in file testsassert.ring 33.4. Assert() Function 237
- 4. CHAPTER THIRTYFOUR DEMO PROGRAMS In this chapter we will see simple demo programs • Language Shell • Main Menu 34.1 Language Shell We can create simple interactive programming environment using the next program while true see nl + "code:> " give cCode try eval(cCode) catch see cCatchError done end Output: code:> see "hello world" hello world code:> for x = 1 to 10 see x + nl next 1 2 3 4 5 6 7 8 9 10 code:> func test see "Hello from test" + nl code:> test() Hello from test code:> bye 238
- 5. Ring Documentation, Release 1.5.3 34.2 Main Menu Example: # Demo Program while true see " Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit " give nMenu see nl # we can use Switch-ON-Other-OFF instead of IF-BUT-ELSE-OK Switch nMenu On 1 sayhello() On 2 Sum() On 3 Stars() On 4 see "Enter Number : " give x see "Output : " Try see Fact(number(x)) Catch see "Error in parameters!" + nl Done On "5" return Other see "bad option" + nl Off end func sayhello see "Enter your name ? " give fname see "Hello " + fname + nl func sum see "number 1 : " give num1 see "number 2 : " give num2 see "Sum : " see 0 + num1 + num2 func stars for x = 1 to 10 see space(8) for y = 1 to x see "*" next see nl next func fact x if x = 0 return 1 else return x * fact(x-1) ok 34.2. Main Menu 239
- 6. Ring Documentation, Release 1.5.3 func space x y = "" for t=1 to x y += " " next return y Output: Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 1 Enter your name ? Mahmoud Fayed Hello Mahmoud Fayed Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 2 number 1 : 3 number 2 : 4 Sum : 7 Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 3 * ** *** **** ***** ****** ******* ******** ********* ********** Main Menu =========== [1] Say Hello [2] Sum two numbers 34.2. Main Menu 240
- 7. Ring Documentation, Release 1.5.3 [3] Stars [4] Fact [5] Exit 4 Enter Number : 5 Output : 120 Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 5 34.2. Main Menu 241
- 8. CHAPTER THIRTYFIVE ODBC FUNCTIONS This chapter contains the ODBC functions provided by the Ring programming language. • odbc_init() • odbc_drivers() • odbc_datasources() • odbc_close() • odbc_connect() • odbc_disconnect() • odbc_execute() • odbc_colcount() • odbc_fetch() • odbc_getdata() • odbc_tables() • odbc_columns() • odbc_autocommit() • odbc_commit() • odbc_rollback() Before using the next function load the odbclib.ring library load "odbclib.ring" # Use ODBC functions 35.1 odbc_init() Function We can create ODBC Handle using the odbc_init() function Syntax: odbc_init() ---> ODBC Handle 242
- 9. Ring Documentation, Release 1.5.3 35.2 odbc_drivers() Function We can get a list of ODBC drivers using the odbc_drivers() function Syntax: odbc_drivers(ODBC Handle) ---> List of Drivers 35.3 odbc_datasources() Function We can get a list of ODBC data sources using the odbc_datasources() function Syntax: odbc_datasources(ODBC Handle) ---> List of Data sources 35.4 odbc_close() Function After the end of using ODBC functions we can free resources using ODBC_Close() function Syntax: odbc_close(ODBC Handle) 35.5 Print List of ODBC Drivers The next example print a list of ODBC drivers. See "ODBC test 1" + nl oODBC = odbc_init() See "Drivers " + nl see odbc_drivers(oODBC) odbc_close(oODBC) Output: ODBC test 1 Drivers Microsoft Access-Treiber (*.mdb) - SQLLevel=0 Driver do Microsoft Paradox (*.db ) - SQLLevel=0 Driver do Microsoft Excel(*.xls) - SQLLevel=0 Microsoft Text Driver (*.txt; *.csv) - SQLLevel=0 Driver da Microsoft para arquivos texto (*.txt; *.csv) - SQLLevel=0 Microsoft dBase-Treiber (*.dbf) - SQLLevel=0 SQL Server - CPTimeout=60 Microsoft Excel Driver (*.xls) - SQLLevel=0 Driver do Microsoft dBase (*.dbf) - SQLLevel=0 Microsoft Paradox-Treiber (*.db ) - SQLLevel=0 Microsoft ODBC for Oracle - CPTimeout=120 Microsoft Text-Treiber (*.txt; *.csv) - SQLLevel=0 Microsoft Excel-Treiber (*.xls) - SQLLevel=0 Microsoft Access Driver (*.mdb) - SQLLevel=0 Driver do Microsoft Access (*.mdb) - SQLLevel=0 35.2. odbc_drivers() Function 243
- 10. Ring Documentation, Release 1.5.3 Microsoft Paradox Driver (*.db ) - SQLLevel=0 Microsoft dBase Driver (*.dbf) - SQLLevel=0 Microsoft Access Driver (*.mdb, *.accdb) - UsageCount=3 Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb) - UsageCount=3 Microsoft Access Text Driver (*.txt, *.csv) - UsageCount=3 SQL Server Native Client 10.0 - UsageCount=1 SQL Server Native Client 11.0 - UsageCount=1 Microsoft Access dBASE Driver (*.dbf, *.ndx, *.mdx) - UsageCount=3 Microsoft Access Paradox Driver (*.db) - UsageCount=3 MySQL ODBC 5.3 ANSI Driver - UsageCount=1 MySQL ODBC 5.3 Unicode Driver - UsageCount=1 ODBC Driver 11 for SQL Server - UsageCount=1 Lianja ODBC Driver - CPTimeout=60 Microsoft Visual FoxPro Driver - UsageCount=1 Microsoft Visual FoxPro-Treiber - UsageCount=1 Driver para o Microsoft Visual FoxPro - UsageCount=1 Microsoft FoxPro VFP Driver (*.dbf) - UsageCount=1 35.6 Print List of ODBC Data Sources The next example print a list of ODBC data sources. See "ODBC test 2" + nl pODBC = odbc_init() See "Data Sources " + nl see odbc_datasources(pODBC) odbc_close(pODBC) Output: ODBC test 2 Data Sources Excel Files - Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb) MS Access Database - Microsoft Access Driver (*.mdb, *.accdb) Customer - Microsoft Access Driver (*.mdb) IdCardData - Microsoft Access Driver (*.mdb) MyProjectData2 - Microsoft Access Driver (*.mdb) MyData - Microsoft Access Driver (*.mdb) MonprojetData - Microsoft Access Driver (*.mdb) dBASE Files - Microsoft Access dBASE Driver (*.dbf, *.ndx, *.mdx) myvfpdata - Microsoft Visual FoxPro Driver FACTORYDATA - Microsoft Access Driver (*.mdb) TRAININGSYSDATA - Microsoft Access Driver (*.mdb) RVCSYSDATASQLDB - SQL Server Native Client 11.0 PWCTRVCDATA - Microsoft Access Driver (*.mdb) MyCompany - Microsoft Access Driver (*.mdb) HCS - Microsoft Access Driver (*.mdb) HCS2 - Microsoft Access Driver (*.mdb, *.accdb) MyProjectData - Microsoft Access Driver (*.mdb) Xtreme Sample Database 2008 - Microsoft Access Driver (*.mdb) Lianja_Southwind - Lianja ODBC Driver Visual FoxPro Database - Microsoft Visual FoxPro Driver Visual FoxPro Tables - Microsoft Visual FoxPro Driver 35.6. Print List of ODBC Data Sources 244