The following tables define all possible ODBC connection attributes for the FreeTDS ODBC driver.  Which ones you'll need depends on how you set yourself up.  They may appear in your connection string, or in odbc.ini.
Table 4.1. Connection attributes used only in connection strings
| Name | Possible Values | Default | Meaning | 
|---|---|---|---|
| DSN | A valid DSN entry | none | The DSNto which FreeTDS should connect. FreeTDS will searchodbc.inifor entry.  It lets you specify a connection as forSQLConnect, but usingSQLDriverConnect.   Do not useServernameandDSNtogether. | 
| UID | Any valid username | none | The username to be used when connecting.  To use domain authentication, specify the domain using the format domain\username. | 
| PWD | Any | empty | The password to be used when connecting. | 
| WSID | Any | Computer name | The name of the local computer, sent to server. Can be specified only for a DSN-less connection. | 
			
			
Table 4.2. Connection attributes that may appear in odbc.ini
| Name | Possible Values | Default | Meaning | 
|---|---|---|---|
| Servername | A valid freetds.confserver section | none | A freetds.confservername, not a hostname as known to DNS. If you want to use ODBC-only configuration, useServerinstead. | 
| Server | A server name or (ip) address | none | Hostname of a server. Used in an ODBC-only configuration. To specify a Microsoft SQL Server instance, use the form server\instance. | 
| Port | Any TCP port | Depends on the TDS version specified with configure | The TCP port where the servername is listening. | 
| TDS_Version | Any valid protocol version | Depends on the TDS version specified with configure | TDS protocol version to use (e.g., 5.0, 7.0). | 
| ClientCharsetorClient_Charset | A name recognized by the iconv library linked to FreeTDS.  Corresponds to client charsetinfreetds.conf.Client_Charsetis for compatibility with NCBI C++ ToolKit. | ISO 8859-1 | Character set (encoding) used by the client. | 
| APP | Free form text, up to 30 characters. | none | Application name. Identifies the connecting application to the server. | 
| Language | Any | us_english | (Human) language the server should use for error messages. | 
| Address | Any | none | IP address of the servername.  Useful if you want to specify a server by address,  rather than by name.  The format is ip,portor simplyipin standard dotted-decimal notation. | 
| Database | Any | none | Specify which database you want to access. If the database does not exist or the user lacks permission to access it, the connection will fail. | 
| TextSize | Any | Server-dependent | Maximum size returned from server for blobs. | 
| PacketSize | Any | Server-dependent | Size of packets to server. Some users saw some performance gain by increasing this value. Normally you shouldn't set it. | 
| Trusted_Connection | Yes/No | No | Use your current account instead of UID/PWDattributes.  This option require SSPI or Kerberos and supersedes anyUID/PWDattributes passed from the application. | 
| Encryption | off/request/require | off | Specify encryption. See encryption on freetds.conf | 
| MARS_Connection | Yes/No | No | Enable MARS for this connection. | 
| UseNTLMv2 | Yes/No | Yes | Use NTLMv2 instead of normal NTLM. Use this option if your Windows domain have this setting. | 
| REALM | Machine domain | none | Kerberos REALM. | 
| ServerSPN | Any valid SPN | MSSQLSvc/server FQDN:port | Full server Kerberos SPN. | 
| AttachDbFilename | server filename (mdf/sdf) | none | MSSQL allow to attach a database while connecting to a server.
This setting allow to do it. You should specify Databaseattribute to set the name of the database that will be used. | 
| DumpFile | Any | File name where to dump logs. | |
| DumpFileAppend | Yes/No | No | |
| DumpFlags | Any | Debug flags. See freetds.conf entries. | |
| ApplicationIntent | ReadWrite/ReadOnly | ReadWrite | Tell application intent. See read-only intenton freetds.conf. | 
| Timeout | Integer number | Query timeout in seconds. |