OTL-Oracle Development Summary

Before using OTL for programming, you must first determine the Oralce version used and the selected character set. OTL supports almost all mainstream databases, and otlv can be enabled through macro

Before using OTL for programming, you must first determine the Oralce version used and the selected character set. OTL supports almost all mainstream databases, and otlv can be enabled through macro

There are also a lot of articles about OTL on the Internet, but it seems that it is only official documents. OTL is very easy to use. Combined with some official examples, you can try more to understand it. After about a month of project development, I have some knowledge about OTL. Here I will summarize it and hope it will help new users who have just started OTL. Some of them, such as the handling of network exceptions, took me two days to solve the problem. Where is my sweat. Start with the question:

I. Preparations before the start

Before using OTL for programming, you must first determine the Oralce version used and the selected character set. OTL supports almost all mainstream databases. You can use the database operation interfaces in otlv4.h through macro.

For example, if you use Oracle 11g R2 and select UTF8 as the character set, you can declare the following two macros before including otlv4.h:

# Define OTL_ORA11G_R2

# Define OTL_ORA_UTF8

# Include "otlv4.h"

....

Ii. Common classes and common members

1. otl_connect class

Static int otl_initialize (const int threaded_mode = 0 ):

The static function used to initialize the OTL environment. The parameter specifies whether it is used for multithreading or single thread. It does not guarantee thread security. That is to say, if multiple threads share the same otl_connect object, they need to be locked for control. A colleague used the default parameter 0 in a multi-threaded environment, causing program exceptions. However, in a single-threaded environment, parameter setting 1 is correct. Therefore, you can set this parameter to 1 directly.

Void rlogon (...):

This function has multiple versions. Please refer to the function declaration corresponding to the corresponding database version in the official documentation. The parameters used in 11g are described as follows:

Const char * connect_str: connection string in the format of "User Name/password @ Database Service name"

Const int aauto_commit: automatic submission mode. If this parameter is set to 0 (default), transactions executed through this connection object are not automatically committed. For example, when you use direct_exec to delete a record, you need to manually call the commit () member function to submit the transaction. If it is set to 1, the transactions enabled through this otl_connect object are automatically committed.

Long direct_exec (...):

Const char * sqlstm: Specifies the "static SQL statement" to be executed, that is, no input or output SQL statement is generated. For example, delete from book whereC ++ ';

DelStream. flush (); // immediately perform the delete operation, although there is only one record in the current stream

Long get_rpc ():

Obtain the number of records affected by the execution of SQL statements in the stream. For example, if 100 records are inserted, 100 is returned when this function is called.

Int good ():

Checks whether the stream object has been opened normally. If yes, 1 is returned. Note: If you reuse a stream object, you must first call the close function to close it, and then call open to open it again.

Int get_dirty_buf_len ():

Obtains the number of records in the buffer zone of the current stream object. The maximum value is the buffer size-1. The system will automatically refresh when the buffer is full. If you call this function after refresh, 0 is returned.

3. otl_exception class

Several Members of this class are used to indicate the exception information, such:

Char pai_text [2048]: SQL statement with an error;

Char var_info [256]: If a bound variable that does not match the actual type is used in the stream, the value of this array is the information of the bound variable;

Unsigned char msg [1000]: I prefer to use it. This array displays specific exception information (including error codes returned by oracle), such as connection timeout.