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ODBCAdaptor

Inherits from: EOAdaptor : NSObject

Declared in: ODBCEOAdaptor/ODBCAdaptor.h

Class Description

An ODBCAdaptor represents a single connection to an ODBC database server, and is responsible for keeping login and model information, performing ODBC-specific formatting of SQL expressions, and reporting errors.

ODBC (Open Data Base Connectivity) defines a standard interface that Windows applications can use to access any data source. Unlike the other Enterprise Objects Frameworks adaptors that support a single type of database, the ODBC adaptor supports any data source that has an ODBC driver. Consequently, in addition to having standard adaptor features, the ODBC adaptor also manages information relating to the driver and to the data types defined by the data source the driver supports.

The ODBCAdaptor class doesn't support nested transactions.

Constants

ODBCAdaptor defines the following string constants for use as connection dictionary keys.

Constant	Corresponding value in the connection dictionary
`dataSourceKey`	The name of the data source to connect to.
`userNameKey`	The name of the user to log in as.
`passwordKey`	The user's password.
`connectionStringKey`	The complete string used to connect to the database. If this key is present in the dictionary, dataSourceKey, userNameKey, and passwordKey are ignored.
`typeInfoKey`	Information about the types supported by the driver.
`driverInfoKey`	Information about driver, including the driver name, version, and so on.

For more information on the connection dictionary, see "The Connection Dictionary" in the ODBCEOAdaptor Framework introduction.

Additionally, ODBCAdaptor defines a string constant for use as a key in an exception's userInfo dictionary.

Constant	Corresponding value in an exception's userInfo dictionary
`SQLStatesKey`	An array of strings. Each string is a five character code corresponding to an ODBC SQL state.

Method Types

Mapping external types to internal types

+ assignExternalTypeForAttribute:

+ externalTypeForOdbcType:model:

+ getOdbcInfoWithConnectionDictionary:

+ odbcTypeForExternalType:model:

+ odbcTypeForStringRepresentation:

+ resetOdbcInfoWithConnectionDictionary:

+ stringRepresentationForOdbcType:

Access information in the connection dictionary

- odbcConnectionString

+ driverInfoForModel:

+ typeInfoForModel:

- driverInfo

- typeInfo

Getting the default Expression Class

- defaultExpressionClass

Getting ODBC environment information

- odbcEnvironment

Class Methods

assignExternalTypeForAttribute:

+ (void)assignExternalTypeForAttribute:(EOAttribute *)attribute

Sets the external information for attribute based on the internal type, precision, and width.

driverInfoForModel:

+ (NSDictionary *)driverInfoForModel:(EOModel *)model

Returns an NSDictionary containing the driver information cached in the connection dictionary of model. If the information is not yet cached in model, connects to the database to get it.

See Also: + typeInfoForModel:, - driverInfo, - typeInfo

externalTypeForOdbcType:model:

+ (NSString *)externalTypeForOdbcType:(int)type model:(EOModel *)model

Returns the external type that represents the best match for an ODBC type in model.

getOdbcInfoWithConnectionDictionary:

+ (NSDictionary *)getOdbcInfoWithConnectionDictionary:(NSDictionary *)connectionDictionary

Sets up the typeInfo and driverInfo dictionaries in connectionDictionary, and returns an updated connection dictionary. Creates an ODBCAdaptor, ODBCContext, and ODBCChannel, and connects to the database to get the information for the typeInfo and driverInfo dictionaries.

odbcTypeForExternalType:model:

+ (NSString *)odbcTypeForExternalType:(NSString *)externalType model:(EOModel *)model

Returns the ODBC type for externalType, as defined in the typeInfo dictionary in model's connection dictionary.

odbcTypeForStringRepresentation:

+ (int)odbcTypeForStringRepresentation:(NSString *)type

Returns the ODBC type (such as SQL_CHAR) for type (such as @"CHAR"). The method stringRepresentationForOdbcType: performs the opposite function: returning a string for a specified ODBC type. These methods are used in conjunction to encode ODBC types in the typeInfo dictionary.

resetOdbcInfoWithConnectionDictionary:

+ (NSDictionary *)resetOdbcInfoWithConnectionDictionary:(NSDictionary *)connectionDictionary

Removes the typeInfo and driverInfo dictionaries from a copy of connectionDictionary and returns the modified connection dictionary.

stringRepresentationForOdbcType:

+ (NSString *)stringRepresentationForOdbcType:(int)type

Returns the string representation of type-for example, for the type SQL_CHAR this method would return the string @"CHAR". The method odbcTypeForStringRepresentation: performs the opposite function: returning the ODBC type for a specified string. These methods are used in conjunction to encode ODBC types in the typeInfo dictionary.

typeInfoForModel:

+ (NSDictionary *)typeInfoForModel:(EOModel *)model

Returns an NSDictionary containing the type information cached in the connection dictionary of model. If the information is not yet cached in model, connects to the database to get it.

Instance Methods

defaultExpressionClass

- (Class)defaultExpressionClass

Returns the ODBCSQLExpression class.

driverInfo

- (NSDictionary *)driverInfo

Returns an NSDictionary containing the driver information cached in the receiver's model's connection dictionary. If the information is not yet cached in the model, connects to the database to get it.

See Also: - typeInfo