SQLBrowseConnect function (CLI) - Get required attributes to connect to data source

Supports an iterative method of discovering and enumerating the attributes and attribute values required to connect to a data source.

Specification:

CLI 5.0
ODBC 1

Each call to SQLBrowseConnect() returns successive levels of attributes and attribute values. When all levels have been enumerated, a connection to the data source is completed and a complete connection string is returned by SQLBrowseConnect(). A return code of SQL_SUCCESS or SQL_SUCCESS_WITH_INFO indicates that all connection information has been specified and the application is now connected to the data source.

Unicode Equivalent: This function can also be used with the Unicode character set. The corresponding Unicode function is SQLBrowseConnectW(). Refer to Unicode functions (CLI) for information about ANSI to Unicode function mappings.

Syntax

SQLRETURN  SQLBrowseConnect (
            SQLHDBC      ConnectionHandle,               /* hdbc */
            SQLCHAR      *InConnectionString,            /* *szConnStrIn */
            SQLSMALLINT  InConnectionStringLength,       /* dbConnStrIn */
            SQLCHAR      *OutConnectionString,           /* *szConnStrOut */
            SQLSMALLINT  OutConnectionStringCapacity,    /* dbConnStrOutMax */
            SQLSMALLINT  *OutConnectionStringLengthPtr); /* *pcbConnStrOut */

Function Arguments

Table 1. SQLBrowseConnect arguments
Data type	Argument	Use	Description
SQLHDBC	ConnectionHandle	input	Connection handle.
SQLCHAR *	InConnectionString	input	Browse request connection string (see InConnectionString argument).
SQLSMALLINT	InConnectionStringLength	input	Number of SQLCHAR elements (or SQLWCHAR elements for the Unicode variant of this function) needed to store *InConnectionString.
SQLCHAR *	OutConnectionString	output	Pointer to a buffer in which to return the browse result connection string (see OutConnectionString argument).
SQLSMALLINT	OutConnectionString Capacity	input	Number of SQLCHAR elements (or SQLWCHAR elements for the Unicode variant of this function) needed to store the *OutConnectionString buffer.
SQLSMALLINT *	OutConnectionString LengthPtr	output	The total number of elements (excluding the null termination character) available to return in OutConnectionString. If the number of elements available to return is greater than or equal to OutConnectionStringCapacity, the connection string in OutConnectionString is truncated to OutConnectionStringCapacity minus the length of a null termination character.

Usage

SQLBrowseConnect() requires an allocated connection. If SQLBrowseConnect() returns SQL_ERROR, outstanding connection information is discarded, and the connection is returned to an unconnected state.

When SQLBrowseConnect() is called for the first time on a connection, the browse request connection string must contain the DSN keyword.

On each call to SQLBrowseConnect(), the application specifies the connection attribute values in the browse request connection string. CLI returns successive levels of attributes and attribute values in the browse result connection string; it returns SQL_NEED_DATA as long as there are connection attributes that have not yet been enumerated in the browse request connection string. The application uses the contents of the browse result connection string to build the browse request connection string for the next call to SQLBrowseConnect(). All mandatory attributes (those not preceded by an asterisk in the OutConnectionString argument) must be included in the next call to SQLBrowseConnect(). Note that the application cannot simply copy the entire content of previous browse result connection strings when building the current browse request connection string; that is, it cannot specify different values for attributes set in previous levels.

When all levels of connection and their associated attributes have been enumerated, CLI returns SQL_SUCCESS, the connection to the data source is complete, and a complete connection string is returned to the application. The connection string is suitable to use as an argument for SQLDriverConnect() in conjunction with the SQL_DRIVER_NOPROMPT option to establish another connection. The complete connection string cannot be used in another call to SQLBrowseConnect(), however; if SQLBrowseConnect() were called again, the entire sequence of calls would have to be repeated.

SQLBrowseConnect() also returns SQL_NEED_DATA if there are recoverable, nonfatal errors during the browse process, for example, an invalid password supplied by the application or an invalid attribute keyword supplied by the application. When SQL_NEED_DATA is returned and the browse result connection string is unchanged, an error has occurred and the application can call SQLGetDiagRec() to return the SQLSTATE for browse-time errors. This permits the application to correct the attribute and continue the browse.

An application can terminate the browse process at any time by calling SQLDisconnect(). CLI will terminate any outstanding connection information and return the connection to an unconnected state.

InConnectionString argument

A browse request connection string has the following syntax:

connection-string ::= attribute[] | attribute: connection-string

attribute ::= attribute-keyword=attribute-value
| DRIVER=[{]attribute-value[}]

attribute-keyword ::= DSN | UID | PWD | NEWPWD
| driver-defined-attribute-keyword

attribute-value ::= character-string
driver-defined-attribute-keyword ::= identifier

where

character-string has zero or more SQLCHAR or SQLWCHAR elements
identifier has one or more SQLCHAR or SQLWCHAR elements
attribute-keyword is case insensitive
attribute-value might be case sensitive
the value of the DSN keyword does not consist solely of blanks
NEWPWD is used as part of a change password request. The application can either specify the new string to use, for example, NEWPWD=anewpass; or specify NEWPWD=; and rely on a dialog box generated by the CLI driver to prompt for the new password

Because of connection string and initialization file grammar, keywords and attribute values that contain the characters []{}(),;?*=!@ should be avoided. Because of the grammar in the system information, keywords and data source names cannot contain the backslash (\) character. For CLI Version 2, braces are required around the DRIVER keyword.

If any keywords are repeated in the browse request connection string, CLI uses the value associated with the first occurrence of the keyword. If the DSN and DRIVER keywords are included in the same browse request connection string, CLI uses whichever keyword appears first.

OutConnectionString argument

The browse result connection string is a list of connection attributes. A connection attribute consists of an attribute keyword and a corresponding attribute value. The browse result connection string has the following syntax:

connection-string ::= attribute[;] | attribute; connection-string

attribute ::= [*]attribute-keyword=attribute-value
attribute-keyword ::= ODBC-attribute-keyword
| driver-defined-attribute-keyword

ODBC-attribute-keyword = {UID | PWD}[:localized-identifier]
driver-defined-attribute-keyword ::= identifier[:localized-identifier]

attribute-value ::= {attribute-value-list} | ?
(The braces are literal; they are returned by CLI.)
attribute-value-list ::= character-string [:localized-character
string] | character-string [:localized-character string], attribute-value-list

where

character-string and localized-character string have zero or more SQLCHAR or SQLWCHAR elements
identifier and localized-identifier have one or more elements; attribute-keyword is case insensitive
attribute-value might be case sensitive

Because of connection string and initialization file grammar, keywords, localized identifiers, and attribute values that contain the characters []{}(),;?*=!@ should be avoided. Because of the grammar in the system information, keywords and data source names cannot contain the backslash (\) character.

The browse result connection string syntax is used according to the following semantic rules:

If an asterisk (*) precedes an attribute-keyword, the attribute is optional, and can be omitted in the next call to SQLBrowseConnect().
The attribute keywords UID and PWD have the same meaning as defined in SQLDriverConnect().
When connecting to a Db2® database, only DSN, UID and PWD are required. Other keywords can be specified but do not affect the connection.
ODBC-attribute-keywords and driver-defined-attribute-keywords include a localized or user-friendly version of the keyword. This might be used by applications as a label in a dialog box. However, UID, PWD, or the identifier alone must be used when passing a browse request string to CLI.
The {attribute-value-list} is an enumeration of actual values valid for the corresponding attribute-keyword. Note that the braces ({}) do not indicate a list of choices; they are returned by CLI. For example, it might be a list of server names or a list of database names.
If the attribute-value is a single question mark (?), a single value corresponds to the attribute-keyword. For example, UID=JohnS; PWD=Sesame.
Each call to SQLBrowseConnect() returns only the information required to satisfy the next level of the connection process. CLI associates state information with the connection handle so that the context can always be determined on each call.

Return codes

SQL_SUCCESS
SQL_SUCCESS_WITH_INFO
SQL_NEED_DATA
SQL_ERROR
SQL_INVALID_HANDLE

Diagnostics

Table 2. SQLBrowseConnect SQLSTATEs
SQLSTATE	Description	Explanation
01000	Warning.	Informational message. (Function returns SQL_SUCCESS_WITH_INFO.)
01004	Data truncated.	The buffer OutConnectionString was not large enough to return entire browse result connection string, so the string was truncated. The buffer OutConnectionStringLengthPtr contains the length of the untruncated browse result connection string. (Function returns SQL_SUCCESS_WITH_INFO.)
01S00	Invalid connection string attribute.	An invalid attribute keyword was specified in the browse request connection string (InConnectionString). (Function returns SQL_NEED_DATA.) An attribute keyword was specified in the browse request connection string (InConnectionString) that does not apply to the current connection level. (Function returns SQL_NEED_DATA.)
01S02	Option value changed.	CLI did not support the specified value of the ValuePtr argument in `SQLSetConnectAttr()` and substituted a similar value. (Function returns SQL_SUCCESS_WITH_INFO.)
08001	Unable to connect to data source.	CLI was unable to establish a connection with the data source.
08002	Connection in use.	The specified connection had already been used to establish a connection with a data source and the connection was open.
08004	The application server rejected establishment of the connection.	The data source rejected the establishment of the connection for implementation defined reasons.
08S01	Communication link failure.	The communication link between CLI and the data source to which it was trying to connect failed before the function completed processing.
28000	Invalid authorization specification.	Either the user identifier or the authorization string or both as specified in the browse request connection string (InConnectionString) violated restrictions defined by the data source.
HY000	General error.	An error occurred for which there was no specific SQLSTATE. The error message returned by `SQLGetDiagRec()` in the *MessageText buffer describes the error and its cause.
HY001	Memory allocation failure.	Db2 CLI is unable to allocate memory required to support execution or completion of the function. It is likely that process-level memory has been exhausted for the application process. Consult the operating system configuration for information about process-level memory limitations.
HY013	Unexpected memory handling error.	Db2 CLI was unable to access memory required to support execution or completion of the function.
HY090	Invalid string or buffer length.	The value specified for argument InConnectionStringLength was less than 0 and was not equal to SQL_NTS. The value specified for argument OutConnectionStringCapacity was less than 0.

Restrictions

None.

Example

  SQLCHAR connInStr[255]; /* browse request connection string */
  SQLCHAR outStr[1025]; /* browse result connection string*/
  
  /* ... */
  
  cliRC = SQL_NEED_DATA;
  while (cliRC == SQL_NEED_DATA)
  {
    /* get required attributes to connect to data source */
    cliRC = SQLBrowseConnect(hdbc,
                             connInStr,
                             SQL_NTS,
                             outStr,
                             sizeof(outStr),
                             &indicator);
    DBC_HANDLE_CHECK(hdbc, cliRC);

    printf("  So far, have connected %d times to database %s\n", 
           count++, db1Alias);
    printf("  Resulting connection string: 

    /* if inadequate connection information was provided, exit
       the program */
    if (cliRC == SQL_NEED_DATA)
    {
      printf("  You can provide other connection information "
             "here by setting connInStr\n");
      break;
    }

    /* if the connection was successful, output confirmation */
    if (cliRC == SQL_SUCCESS)
    {
      printf("  Connected to the database 
    }
  }