SQLDataSources Function
Conformance
Version Introduced: ODBC 1.0 Standards Compliance: ISO 92
Summary
SQLDataSources returns information about a data source. This function is implemented only 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 about. 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.
If ServerName is NULL, NameLength1Ptr will still return the total number of characters (excluding the null-termination character for character data) available to return in the buffer pointed to by ServerName.
BufferLength1
[Input] Length of the *ServerName buffer, in characters; 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 characters (excluding the null-termination character) available to return in *ServerName. If the number of characters 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.
If Description is NULL, NameLength2Ptr will still return the total number of characters (excluding the null-termination character for character data) available to return in the buffer pointed to by Description.
BufferLength2
[Input] Length in characters of the *Description buffer.
NameLength2Ptr
[Output] Pointer to a buffer in which to return the total number of characters (excluding the null-termination character) available to return in *Description. If the number of characters 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 can be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_ENV and a Handle of EnvironmentHandle. The following table lists the SQLSTATE values typically 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.
| SQLSTATE | Error | Description |
|---|---|---|
| 01000 | General warning | (DM) Driver Manager-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.) |
| 01004 | String data, right truncated | (DM) The buffer *ServerName was not large enough to return the complete data source name. Therefore, the name was truncated. The length of the entire data source name is returned in *NameLength1Ptr. (Function returns SQL_SUCCESS_WITH_INFO.) (DM) The buffer *Description was not large enough to return the complete driver description. Therefore, the description was truncated. The length of the untruncated data source description is returned in *NameLength2Ptr. (Function returns SQL_SUCCESS_WITH_INFO.) |
| HY000 | General error | (DM) An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause. |
| HY001 | Memory allocation error | (DM) The Driver Manager was unable to allocate memory that is required to support execution or completion of the function. |
| HY010 | Function sequence error | (DM) SQLExecute, SQLExecDirect, or SQLMoreResults was called for the StatementHandle and returned SQL_PARAM_DATA_AVAILABLE. This function was called before data was retrieved for all streamed parameters. |
| HY013 | Memory management error | The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions. |
| HY090 | Invalid string or buffer length | (DM) The value specified for argument BufferLength1 was less than 0. (DM) The value specified for argument BufferLength2 was less than 0. |
| HY103 | Invalid retrieval code | (DM) The value specified for the argument Direction was not equal to SQL_FETCH_FIRST, SQL_FETCH_FIRST_USER, SQL_FETCH_FIRST_SYSTEM, or SQL_FETCH_NEXT. |
| HY117 | Connection is suspended due to unknown transaction state. Only disconnect and read-only functions are allowed. | (DM) For more information about suspended state, see SQLEndTran Function. |
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.
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
| For information about | See |
|---|---|
| Discovering and listing values required to connect to a data source | SQLBrowseConnect Function |
| Connecting to a data source | SQLConnect Function |
| Connecting to a data source using a connection string or dialog box | SQLDriverConnect Function |
| Returning driver descriptions and attributes | SQLDrivers Function |