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SybaseContext

Inherits from: EOAdaptorContext : NSObject

Declared in: SybaseEOAdaptor/SybaseContext.h

Class Description

A SybaseContext represents a single transaction scope on the database server to which its adaptor object is connected. Since a Sybase server supports multiple concurrent transaction sessions, the adaptor may have several adaptor contexts. A SybaseContext may in turn have a SybaseChannel, which handles actual access to the data on the server.

The features the SybaseContext class adds to EOAdaptorContext are methods for returning Sybase-specific data structures that describe characteristics of the context. The method contextPointer returns the Sybase global context pointer, so that you can make direct calls to the Sybase client library. The method connection returns the SybaseContext's CT library connection (CS_CONNECTION *).

The SybaseContext can have a delegate, which gives you access to all messages returned from the Sybase client library or from the Sybase Server. See the SybaseContext Delegate protocol specification for a complete description.

Method Types

Getting the context pointer

+ contextPointer

Setting the login time out interval

+ loginTimeOutInterval

+ setLoginTimeOutInterval:

Setting the time out interval

+ setTimeOutInterval:

+ timeOutInterval

Managing the connection

- connect

- connection

- currentChannel

- disconnect

- isConnected

+ setMaximumConnections:

+ maximumConnections

Setting the max text size default

- maxTextSizeDefault

- setMaxTextSizeDefault:

Setting the current exception

- raiseCurrentException

- setCurrentException:

Class Methods

contextPointer

+ (void *)contextPointer

Returns the Sybase global context pointer (CS_CONTEXT *). You can use this to make direct calls to the Sybase client library.

maximumConnections

public static int maximumConnections()

+ (int)maximumConnections

Returns the value for CS_MAX_CONNECT, the maximum number of database connections a Sybase client process can have open simultaneously.

loginTimeOutInterval

+ (int)loginTimeOutInterval

Returns the login time out interval used by SybaseContext.

See Also: + setLoginTimeOutInterval:

setLoginTimeOutInterval:

+ (void)setLoginTimeOutInterval:(int)seconds

Sets the login time out interval value SybaseContext uses during the creation of new channels. The default is 0, which means that there is no time out.

See Also: + loginTimeOutInterval

setMaximumConnections:

+(BOOL)setMaximumConnections:(int)value

Sets CS_MAX_CONNECT, the maximum number of database connections a Sybase client process can have open simultaneously. Returns YES if the operation is successful. By default the adaptor uses the Sybase client library default, which is normally sufficient. However, if your application communicates with many databases or uses database authentication for each user, you might need to raise the limit. It is possible to raise the limit after database connections have been opened.

setTimeOutInterval:

+ (void)setTimeOutInterval:(int)seconds

Sets the time out interval value that the SybaseContext uses during the creation of new channels. The default is 0, which means that there is no time out.

See Also: + timeOutInterval

timeOutInterval

+ (int)timeOutInterval

Returns the time out interval used by SybaseContext.

Instance Methods

connect

- (void)connect

Opens a connection to the database server. SybaseChannel sends this message to SybaseContext when it (SybaseChannel) is about to open a channel to the server.

See Also: - disconnect

connection

- (void *)connection

Returns the CT library connection (CS_CONNECTION *) for the receiver.

currentChannel

- (SybaseChannel *)currentChannel

Returns the SybaseChannel currently associated with the receiving context.

disconnect

- (void)disconnect

Closes a connection to the database server. SybaseChannel sends this message to SybaseContext when it (SybaseChannel) has just closed a channel to the server.

See Also: - connect

isConnected

- (BOOL)isConnected

Returns YES if the receiver has an open connection to the database, NO otherwise.

See Also: - connect, - disconnect

maxTextSizeDefault

- (int)maxTextSizeDefault

Returns the maximum number of bytes to be returned from a Sybase image to text field. The default is set to INT_MAX, as defined for the host machine. This number can be overwritten on a per-channel basis by sending the appropriate SQL to the channel using the evaluateExpression: method.

raiseCurrentException

- (void)raiseCurrentException

If the receiver has an exception, raises it.

See Also: - setCurrentException:

setCurrentException:

- (void)setCurrentException:(NSException *)exception

Sets the receiver's current exception to exception.

When the SybaseAdaptor encounters an error, it uses the error message to build an NSException and stores the exception in the SybaseContext using this method. The exception can then be reviewed by other components to determine if the error is fatal.

See Also: - raiseCurrentException

setMaxTextSizeDefault:

- (void)setMaxTextSizeDefault:(int)textSize

Sets the receiver's default text size to textSize. Any channels created after this method has been invoked will use the newly specified text size.