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

SQLGetDiagRec

Conformance

Version Introduced: ODBC 3.0
Standards Compliance: ISO 92

Summary

SQLGetDiagRec returns the current values of multiple fields of a diagnostic record that contains error, warning, and status information. Unlike SQLGetDiagField, which returns one diagnostic field per call, SQLGetDiagRec returns several commonly used fields of a diagnostic record, including the SQLSTATE, the native error code, and the diagnostic message text.

Syntax

SQLRETURN SQLGetDiagRec(
     SQLSMALLINT     HandleType,
     SQLHANDLE     Handle,
     SQLSMALLINT     RecNumber,
     SQLCHAR *     Sqlstate,
     SQLINTEGER *     NativeErrorPtr,
     SQLCHAR *     MessageText,
     SQLSMALLINT     BufferLength,
     SQLSMALLINT *     TextLengthPtr);

Arguments

HandleType

[Input]
A handle type identifier that describes the type of handle for which diagnostics are required. Must be one of the following:

SQL_HANDLE_ENV
SQL_HANDLE_DBC
SQL_HANDLE_STMT
SQL_HANDLE_DESC

Handle

[Input]
A handle for the diagnostic data structure, of the type indicated by HandleType. If HandleType is SQL_HANDLE_ENV, Handle can be either a shared or an unshared environment handle.

RecNumber

[Input]
Indicates the status record from which the application seeks information. Status records are numbered from 1.

SQLState

[Output]
Pointer to a buffer in which to return a five-character SQLSTATE code pertaining to the diagnostic record RecNumber. The first two characters indicate the class; the next three indicate the subclass. This information is contained in the SQL_DIAG_SQLSTATE diagnostic field. For more information, see "SQLSTATEs" in Chapter 15, "Diagnostics."

NativeErrorPtr

[Output]
Pointer to a buffer in which to return the native error code, specific to the data source. This information is contained in the SQL_DIAG_NATIVE diagnostic field.

MessageText

[Output]
Pointer to a buffer in which to return the diagnostic message text string. This information is contained in the SQL_DIAG_MESSAGE_TEXT diagnostic field. For the format of the string, see the "Diagnostic Messages" section of Chapter 15, "Diagnostics."

BufferLength

[Input]
Length of the *MessageText buffer in characters. There is no maximum length of the diagnostic message text.

TextLengthPtr

[Output]
Pointer to a buffer in which to return the total number of bytes (excluding the number of bytes required for the null-termination character) available to return in *MessageText. If the number of bytes available to return is greater than BufferLength, the diagnostic message text in *MessageText is truncated to BufferLength minus the length of a null-termination character.

Returns

SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_ERROR, or SQL_INVALID_HANDLE.

Diagnostics

SQLGetDiagRec does not post diagnostic records for itself. It uses the following return values to report the outcome of its own execution:

• SQL_SUCCESS: The function successfully returned diagnostic information.
  
  
• SQL_SUCCESS_WITH_INFO: The *MessageText buffer was too small to hold the requested diagnostic message. No diagnostic records were generated. To determine that a truncation occurred, the application must compare BufferLength to the actual number of bytes available, which is written to *StringLengthPtr.
  
  
• SQL_INVALID_HANDLE: The handle indicated by HandleType and Handle was not a valid handle.
  
  
• SQL_ERROR: One of the following occurred:
  • RecNumber was negative or 0.
    
    
  • BufferLength was less than zero.
• SQL_NO_DATA: RecNumber was greater than the number of diagnostic records that existed for the handle specified in Handle. The function also returns SQL_NO_DATA for any positive RecNumber if there are no diagnostic records for Handle.

Comments

An application typically calls SQLGetDiagRec when a previous call to an ODBC function has returned SQL_SUCCESS or SQL_SUCCESS_WITH_INFO. However, because any ODBC function can post zero or more diagnostic records each time it is called, an application can call SQLGetDiagRec after any ODBC function call. An application can call SQLGetDiagRec multiple times to return some or all of the records in the diagnostic data structure. ODBC imposes no limit to the number of diagnostic records that can be stored at any one time.

SQLGetDiagRec cannot be used to return fields from the header of the diagnostic data structure. (The RecNumber argument must be greater than 0.) The application should call SQLGetDiagField for this purpose.

SQLGetDiagRec retrieves only the diagnostic information most recently associated with the handle specified in the Handle argument. If the application calls another ODBC function, except SQLGetDiagRec, SQLGetDiagField, or SQLError, any diagnostic information from the previous calls on the same handle is lost.

An application can scan all diagnostic records by looping, incrementing RecNumber, as long as SQLGetDiagRec returns SQL_SUCCESS. Calls to SQLGetDiagRec are nondestructive to the header and record fields. The application can call SQLGetDiagRec again at a later time to retrieve a field from a record as long as no other function, except SQLGetDiagRec, SQLGetDiagField, or SQLError, has been called in the interim. The application can also retrieve a count of the total number of diagnostic records available by calling SQLGetDiagField to retrieve the value of the SQL_DIAG_NUMBER field, and then calling SQLGetDiagRec that many times.

For a description of the fields of the diagnostic data structure, see SQLGetDiagField. For more information, see "Using SQLGetDiagRec and SQLGetDiagField" and "Implementing SQLGetDiagRec and SQLGetDiagField" in Chapter 15, "Diagnostics."

HandleType Argument

Each handle type can have diagnostic information associated with it. The HandleType argument denotes the handle type of the Handle argument.

Some header and record fields cannot be returned for environment, connection, statement, and descriptor handles. Those handles for which a field is not applicable are indicated in the "Header Fields" and "Record Fields" sections in SQLGetDiagField.

A call to SQLGetDiagRec will return SQL_INVALID_HANDLE if HandleType is SQL_HANDLE_SENV, which denotes a shared environment handle. However, if HandleType is SQL_HANDLE_ENV, Handle can be either a shared or an unshared environment handle.

Related Functions