Luxena dbExpress driver for Informix Pro online manual product home
Overview
Connection string feature
Compatibility
IInformixConnection interface
Luxena dbExpress driver for Informix Pro manual
Connection string feature
Connection string feature is a method of configuring dbExpress driver for Informix Pro. Physically connection string feature is a "HostName" parameter that exists in TSQLConnection.Params collection. Connection string is a semicolon separated collection of name-value pairs.
Runtime connection string feature utilizing example:
SQLConnection.Params.Values['HostName'] := 'InformixServer=server; Client_Locale=en_us.8859-1; Fet_Buf_Size=32767; OptOFC=1; AutoCommit=True; BlobSize=-1; WaitOnLocks=False; CommitRetain=False; IsolationLevel=ReadCommitted; Trim Char=False; money=currency; decimal=bcd; int8=fmtbcd; lvarchar=string';
Why connection string is useful?
Connection string allows developers flexible configure driver parameters, including all setnet32 parameters and peculiar driver's parameters that affects performance, transaction management, etc. and are not available through standard dbExpress configuration.
Avoids configuration constraints that are common to standard dbExpress configuration by TSQLConnection.Params. For example, it is possible to force driver to trim chars in Delphi 6, where Trim Char configuration parameter is absent in dbExpress configuration.
With connection string developers are able to specify all Informix Connect parameters needed for connection without configuring Informix connectivity software. This feature makes the deploying of applications much easier allowing install the Informix Client without need to configure it.
Standard to connection string parameters mapping
For backward compatibility dbExpress driver for Informix Pro supports standard dbExpress configuration parameters that are available in TSQLConnection.Params collection.
dbExpress configuration parameter driver Pro connection string parameter
SERVERCHARSET CLIENT_LOCALE
HOSTNAME INFORMIXSERVER
AUTOCOMMIT AUTOCOMMIT
BLOBSIZE BLOBSIZE
WAITONLOCKS WAITONLOCKS
COMMITRETAIN COMMITRETAIN
INFORMIXLUXENA TRANSISOLATION ISOLATIONLEVEL
TRIM CHAR TRIM CHAR
 standard dbExpress configuration parameters have higher priority against connection string parameters.
Connection string parameters description
Connection string may contain parameter of two kinds:
1) Custom parameters of dbExpress driver for Informix Pro;
2) Informix connectivity environment variables. Majority of which are available by means of setnet32 utility.
Custom parameters of dbExpress driver for Informix Pro
parameter purpose possible values
AUTOCOMMIT specifies an action, commit(true) or rollback(false), that have to be executed if there is an active transaction on disconnect.
also, for ansi database specifies whether the connection should commit transaction after every statement execution. 		true or false.
Default is true.
BLOBSIZE specifies the number of kilobytes of BLOB data that is fetched for BLOB fields if BLOBSIZE = -1 then fetch data size calculated automatically otherwise it specifies maximum size of fetched data.
Default is -1.
COMMITRETAIN specifies cursor behaviour when a commit or rollback transaction is called. true (close cursor) or false (preserve cursor).
Default is true.
DECIMAL mapping of Informix data type to VCL data type Float, Currency, Bcd or FmtBcd.
Default is Bcd.
INT8 mapping of Informix data type to VCL data type Float, Currency, Bcd or FmtBcd.
Default is FmtBcd.
ISOLATIONLEVEL defines the degree of concurrency among processes that attempt to access the same rows simultaneously DIRTYREAD, CURSORSTABILITY, REPEATABLEREAD or READCOMMITTED.
Default is READCOMMITTED
LVARCHAR mapping of Informix data type to VCL data type Blob or String.
Default is String.
MONEY mapping of Informix data type to VCL data type Float, Currency, Bcd or FmtBcd.
Default is Currency.
TRIM CHAR trims trailing spaces from a data CHAR type true or false.
Default is false.
WAITONLOCKS defines how the database server handles a process that tries to access a locked row or table. true (infinitly wait), false (not wait) or number of seconds to wait.
Default is false.
THREAD MODE defines usage mode in threads. Informix connectivity allows only one active connection per thread, so if more than one connection are used in thread or connection is used in several threads, application must switch active connection for an execution thread. ONE PER THREAD, MANY PER THREAD, INTERTHREADED (FETCH OPTIMIZED) and INTERTHREADED.
Default is INTERTHREADED (FETCH OPTIMIZED).
 all connection string parameters' values are case insensitive.
Informix connectivity environment variables
Informix Client SDK, Version 2.5, supports the following environment variables. For more information on these environment variables, see their descriptions in the respective Informix manuals.
IBM Informix Client Products Installation Guide which contains following environments variables available here.
parameter purpose possible values
CC8BITLEVEL Specifies how the C-language compiler processes non-ASCII (8-bit and multibyte) characters. Default is 2.
CLIENT_LOCALE Specifies the locale that the client application uses to perform read/write operations that involve the keyboard, display, file, or printer on the client computer. Any valid locale specifier. No default.
COLLCHAR Specifies a collation sequence for characters. Provided for backward compatibility with NLS products.
DB_LOCALE Specifies the locale of all the databases that a client application accesses in a single connection (the database locale).
DBALSBC When set to 1, enables compatibility with ALS products. Values: 0 or 1.
DBANSIWARN When turned on (y), causes the preprocessor to check for Informix extensions to ANSI-standard SQL syntax at compile time and causes an application to check for Informix extensions at runtime. Default is n.
DBAPICODE Enables pre-7.2 systems that use nonstandard or rare code sets to access databases that store data in a standard code set. Maximum size = 23 characters. Provided for backward compatibility with NLS and ALS products.
DBASCIIBC When set to 1, enables compatibility with ASCII products. Values: 0 or 1.
DBCENTURY Specifies how to expand values of two-digit-year DATE and DATETIME values. P = past century, R = present century, C = closest century. Values: P, R, or C Default is R.
DBCODESET Specifies an Asian-locale code set. Overrides the code set that DB_LOCALE specifies. Provided for backward compatibility with Version 4.x and 5. ALS products. Same values as ALS DBAPICODE. Default is 8859-1: (unless the informix.rc file specifies another system-wide default)
DBCONNECT Specifies whether or not connections are restricted. Values: 1 or 3
DBCSCONV Controls code-set conversion initialization. Maximum size is eight characters. Provided for backward compatibility with ALS products. Values: 1 or 2:codesetname. See 5.0 ALS documentation.
DBCSOVERRIDE Forces the user-specified DB_LOCALE value to override default restrictions on accessing databases with locales different from DB_LOCALE. Provided for backward compatibility with Version 6.0 ALS database servers. Values: 0 or 1.
DBCSWIDTH Maximum number of display bytes (1-2) and storage bytes (1-4) for the characters in up to three code sets. Display and storage widths are separated by commas; code sets are separated by colons. Maximum size of this field is, therefore, 11 characters. Provided for backward compatibility with ALS products. Example: 1,1:2,3 means a display and storage width of 1 byte for character set 1; a display width of 2 bytes and a storage width of 3 bytes for code set 2.
DBDATE Specifies the end-user format for DATE values so that they can conform with various international date conventions. Provided for backward compatibility with pre-7.2 products. Informix recommends GL_DATE for 7.2 ESQL/C applications. Default is MDY4 unless NLS variable LC_TIME is activated.
DBFLTMASK Specifies the number of decimal digits to use when storing a DECIMAL, SMALLFLOAT, or FLOAT data type in a character buffer. Values: 0-16. Default is 16.
DBLANG Specifies the subdirectory of the Informix installation directory that contains the product-specific message (.iem) files. Default is \msg.
DBMONEY Specifies the end-user format for MONEY values so that they can conform with various international and local monetary conventions. Default is $.,.
DBMONEYSCALE Specifies the total number of digits and number of decimal digits for monetary values. Provided for backward compatibility with ALS products.
DBNLS Specifies whether an application can access NLS features. Provided for backward compatibility with NLS products. Default is n.
DBPATH Identifies the database servers that contain databases that the application accesses.
DBSS2 Maximum size is four characters. Provided for backward compatibility with ALS products. Values: 0x00-0xff or 0-255
DBSS3 Maximum size is four characters. Provided for backward compatibility with ALS products. Values: 0x00-0xff or 0-255
DBTEMP Specifies the directory on the client computer that the client processor uses to store temporary files (also called swap files). Default is \tmp.
DBTIME Specifies the end-user format for DATETIME values so that they can conform with various international date conventions. Informix recommends GL_DATETIME for 7.2 ESQL/C applications. Provided for backward compatibility with pre-7.2 products. Default is %Y-%m-%d %H:%M:%S.
DELIMIDENT Indicates whether (y) or not (n) to interpret strings in double quotes as delimited identifiers. Default is n.
ESQLMF Indicates whether the ESQL/C processor automatically invokes the ESQL/C multibyte filter (value=1 and CC8BITLEVEL<3, or not value=0).
FET_BUF_SIZE Overrides the default size of the fetch buffer. Any valid buffer size, in bytes. Default value depends on row size.
GL_DATE Specifies a customized end-user format for DATE values.
GL_DATETIME Specifies a customized end-user format for DATETIME values.
IFX_NOZEROMDY
IFX-USE_PREC_16
INFORMIXCONRETRY Specifies the maximum number of additional connection attempts made to a database server in the time limit that CONTIME specifies. Default is 1.
INFORMIXCONTIME Specifies the number of seconds an SQL CONNECT statement continues to try to establish a connection before it generates an error. Default is 15.
INFORMIXDIR Identifies the location of the client programs, library files, message files, header files, and other Informix software components. Default is C:\INFORMIX.
INFORMIXSERVER Identifies the default database server.
INFORMIXSQLHOSTS Specifies the name of the computer on which the central registry resides.
LANG Specifies the language environment (called a locale) for an NLS database that an application accesses. Provided for backward compatibility with NLS products. Default is C.
LC_COLLATE Specifies a collation or sort sequence for data in NCHAR and NVARCHAR columns of an NLS database. Provided for backward compatibility with NLS products. Default is the value that LANG specifies.
LC_CTYPE Specifies character attributes such as character classification and case conversion of regular expressions for data in NCHAR and NVARCHAR columns of an NLS database. Provided for backward compatibility with NLS products. Default is the value that LANG specifies.
LC_MONETARY Specifies the end-user format for MONEY values in an NLS database. Provided for backward compatibility with NLS products. Default is the value that LANG specifies.
LC_NUMERIC Specifies the end-user format for numeric values in an NLS database. Provided for backward compatibility with NLS products. Default is the value that LANG specifies.
LC_TIME Specifies the end-user format for DATE and DATETIME values in an NLS database. Provided for backward compatibility with NLS products. Default is the value that LANG specifies.
NODEFDAC Allows default table privileges for PUBLIC when a new table is created in a database that is not ANSI compliant. Default is to allow privileges.
OPTMSG Enables optimized message transfers (message chaining) for all SQL statements in an application. Default is the value that LANG specifies.
OPTOFC Enables optimize-OPEN-FETCH-CLOSE functionality in an Informix ESQL/C application that uses DECLARE and OPEN statements to execute a cursor. Default is the value that LANG specifies.
USE_DTENV Enables support for non-ANSI datetime formats in ESQL/C client programs.
Informix connectivity environment variables for Microsoft Windows
Following parameters affects only windows installations of Informix connectivity. Although, this parameters are present in setnet32 without "win32" prefix using of them on windows platform is valid only with "win32" followed by parameter name without any separating character. For example, WIN32SERVICE stands for SERVICE parameter.
parameter purpose possible values
WIN32PROTOCOL identifies which Network Protocol should be used olsoctcp, onsoctcp, olsocspx, onsocspx, sesoctcp, sesocspx, seipcpip or olipcnmp
WIN32SERVICE the ServiceName that the remote database server uses to listen to all incoming requests
WIN32USER Informix login user name
WIN32PASS Informix login user password
WIN32OPTIONS defines options specific to the database server. Refer to Server Administrator's Guide for more information.
WIN32HOST the name of the host machine where Informix server resides
WIN32ASKPASSWORD specifies whether your application is to prompt for password at the time of connection to a server, has no password or you provide password by means of WIN32PASS environment variable y (ask password at runtime), n (no password) or p (password)