10. Understanding ODBC Connectivity : Connection String Keywords
 
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Connection String Keywords
If your application requires a connection string to connect to a data source, you must specify the data source name. Optionally, you can specify attribute=value pairs to override certain data source and vnode definitions. The ODBC function SQLDriverConnect() or SQLDriverConnectW() is required for connection strings.
The connection string has the form:
DSN=data_source_name[;attribute=value[;attribute=value]...]
Alternatively, you can bypass data source definitions entirely if you include sufficient information in the connection string. The minimum attributes in this case are the SERVER, SERVERTYPE, and DATABASE attribute=value pairs.
Connection strings that bypass the DSN definition have the form:
CONNECTSTR=SERVER=server_name; SERVERTYPE=server_type; DATABASE=database;[attribute=value]...]
The following table provides the keywords for each connection string attribute.
Keyword
Attribute Value Description
DSN
Data source name.
DRIVER
Driver description as returned by SQLDrivers().
UID
User ID to override vnode definition.
PWD
Password to override vnode definition. If specified, UID must also be specified.
DBMS_PWD
Database password. Database passwords are defined by the CREATE USER statement, Director, accessdb, or VDBA.
Although supported as a connection string attribute, DBMS_PWD is not supported as a DSN configuration attribute.
SERVER
Vnode name (see page Tools for Defining Vnodes).
SERVERTYPE
Server type (for example, INGRES, IDMS, or DB2).
DATABASE
Database name as defined on the server.
DB
A synonym for DATABASE.
ROLENAME
Role name to override vnode definition.
ROLEPWD
Role password to override vnode definition.
GROUP
Group identifier for the session. Equivalent to the -G flag of the Ingres command-line flags.
BLANKDATE
=NULL
Indicates that the driver must return empty string DATE values as NULL.
DATEALIAS
Specifies the data type of columns created using the alias keyword DATE. Valid values are: ANSIDATE or INGRESDATE. The attribute can be left unset. Default value is unset.
This setting overrides the date_alias setting in config.dat. If left unset, the date_alias setting in config.dat is used. If neither the ODBC nor config.dat specify a date alias, the default is INGRESDATE.
SENDDATETIMEASINGRESDATE
Specifies whether to send date/timestamp values as INGRESDATE data type. Valid values are:
false–Send values as ANSI TIMESTAMP WITH TIMEZONE type
true–Send values as INGRESDATE type
unset—Implicitly send ANSIDATE or INGRESDATE, depending on the DATEALIAS property:
If DATEALIAS property is set to ANSIDATE, uses a value of false; otherwise uses a value of true. Unlike DATEALIAS, this property affects the way parameter data is handled.
DATE1582
=NULL
Indicates that the driver must return values of ‘1582-01-01’ as NULL.
DATE
Same as DATE1582 keyword.
SELECTLOOPS
=N
Indicates that Cursor Loops must be used.
CATCONNECT
=Y
Indicates that a second separate Ingres session must be used for catalog functions (SQLTables, and so on).
NUMERIC_ OVERFLOW
=IGNORE
Indicates that no error is issued if an arithmetic error of numeric overflow, underflow, or divide by zero occur.
Equivalent to “-numeric_overflow=ignore” command line flag.
CATSCHEMANULL
=Y
Returns NULL for schema names from ODBC catalog functions.
CONVERTINT8TOINT4
=Y
Coerces eight-byte (i8) integer values from the DBMS to four-byte (i4).
ALLOWUPDATE
=Y
Allows updates on sessions set to read-only.
DEFAULTTOCHAR
=Y
Treats Unicode strings as "standard" (multi-byte) strings.
MULTIBYTEFILLCHAR
=c
Displays the specified character (c) for each character that fails to convert from Unicode. This option is for applications that display Unicode data as multi-byte.
This attribute can be specified if no ODBC DSN is defined or to override the "Fill character for failed Unicode/multibyte conversions" setting in the ODBC DSN.
DISABLEUNDERSCORE
=Y
Disables underscore wildcard search characters in catalog function.