MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 21: ODBC API Reference

SQLDataSources

Conformance

Version Introduced: ODBC 1.0
Standards Compliance: ISO 92

Summary

SQLDataSources returns information about a data source. This function is implemented solely by the Driver Manager.

Syntax

SQLRETURN SQLDataSources(
     SQLHENV     EnvironmentHandle,
     SQLUSMALLINT     Direction,
     SQLCHAR *     ServerName,
     SQLSMALLINT     BufferLength1,
     SQLSMALLINT *     NameLength1Ptr,
     SQLCHAR *     Description,
     SQLSMALLINT     BufferLength2,
     SQLSMALLINT *     NameLength2Ptr);

Arguments

EnvironmentHandle

[Input]
Environment handle.

Direction

[Input]
Determines which data source the Driver Manager returns information on. Can be:

SQL_FETCH_NEXT (to fetch the next data source name in the list), SQL_FETCH_FIRST (to fetch from the beginning of the list), SQL_FETCH_FIRST_USER (to fetch the first user DSN), or SQL_FETCH_FIRST_SYSTEM (to fetch the first system DSN).

When Direction is set to SQL_FETCH_FIRST, subsequent calls to SQLDataSources with Direction set to SQL_FETCH_NEXT return both user and system DSNs. When Direction is set to SQL_FETCH_FIRST_USER, all subsequent calls to SQLDataSources with Direction set to SQL_FETCH_NEXT return only user DSNs. When Direction is set to SQL_FETCH_FIRST_SYSTEM, all subsequent calls to SQLDataSources with Direction set to SQL_FETCH_NEXT return only system DSNs.

ServerName

[Output]
Pointer to a buffer in which to return the data source name.

BufferLength1

[Input]
Length of the *ServerName buffer, in bytes; this does not need to be longer than SQL_MAX_DSN_LENGTH plus the null-termination character.

NameLength1Ptr

[Output]
Pointer to a buffer in which to return the total number of bytes (excluding the null-termination byte) available to return in *ServerName. If the number of bytes available to return is greater than or equal to BufferLength1, the data source name in *ServerName is truncated to BufferLength1 minus the length of a null-termination character.

Description

[Output]
Pointer to a buffer in which to return the description of the driver associated with the data source. For example, dBASE or SQL Server.

BufferLength2

[Input]
Length of the *Description buffer.

NameLength2Ptr

[Output]
Pointer to a buffer in which to return the total number of bytes (excluding the null-termination byte) available to return in *Description. If the number of bytes available to return is greater than or equal to BufferLength2, the driver description in *Description is truncated to BufferLength2 minus the length of a null-termination character.

Returns

SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_NO_DATA, SQL_ERROR, or SQL_INVALID_HANDLE.

Diagnostics

When SQLDataSources returns either SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value may be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_ENV and a Handle of EnvironmentHandle. The following table lists the SQLSTATE values commonly returned by SQLDataSources and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.

Comments

Because SQLDataSources is implemented in the Driver Manager, it is supported for all drivers regardless of a particular driver's standards compliance.

An application can call SQLDataSources multiple times to retrieve all data source names. The Driver Manager retrieves this information from the system information. When there are no more data source names, the Driver Manager returns SQL_NO_DATA. If SQLDataSources is called with SQL_FETCH_NEXT immediately after it returns SQL_NO_DATA, it will return the first data source name. For information about how an application uses the information returned by SQLDataSources, see "Choosing a Data Source or Driver" in Chapter 6, "Connecting to a Data Source or Driver."

If SQL_FETCH_NEXT is passed to SQLDataSources the very first time it is called, it will return the first data source name.

The driver determines how data source names are mapped to actual data sources.

Related Functions