Is One Temporary LOB Locator Equal to Another

Figure 10-16 Use Case Diagram: See If One (Temporary) LOB Locator Is Equal to Another

See: "Use Case Model: Internal Temporary LOBs", for all basic operations of Internal Temporary LOBs.

Purpose

This procedure describes how to see if one LOB locator for a temporary LOB is equal to another.

Usage Notes

If two locators are equal, this means that they refer to the same version of the LOB data (see "Read-Consistent Locators" in Chapter 5, "Advanced Topics").

Syntax

See Chapter 3, "LOB Programmatic Environments" for a list of available functions in each programmatic environment. Use the following syntax references for each programmatic environment:

• PL/SQL (DBMS_LOB): There is no applicable syntax reference for this use case.

• C (OCI): Oracle Call Interface Programmer's Guide Chapter 15, "Relational Functions" -- LOB Functions, OCILobIsEqual

• COBOL (Pro*COBOL): There is no applicable syntax reference for this use case.

• C/C++ (Pro*C/C++): Pro*C/C++ Precompiler Programmer's Guide Appendix F, "Embedded SQL Statements and Directives" -- LOB ASSIGN. See also C(OCI) function, OCILobIsEqual

• Visual Basic (OO4O): There is no applicable syntax reference for this use case.

• Java (JDBC): There is no applicable syntax reference for this use case.

Scenario

Not applicable.

Examples

Examples are provided in the following programmatic environments:

• PL/SQL (DBMS_LOB Package). No example is provided with this release.

• C (OCI): See If One LOB Locator for a Temporary LOB Is Equal to Another

• COBOL (Pro*Cobol): No example is provided with this release.

• C/C++ (Pro*C/C++): See If One LOB Locator for a Temporary LOB Is Equal to Another

• Visual Basic (OO4O): No example is provided with this release.

• Java (JDBC): No example is provided with this release.

C (OCI): See If One LOB Locator for a Temporary LOB Is Equal to Another

sb4 ck_isequal (OCIError      *errhp,
                OCISvcCtx     *svchp,
                OCIStmt       *stmthp,
                OCIEnv        *envhp)
{
  OCILobLocator *loc1;
  OCILobLocator *loc2;
  boolean is_equal;
  is_equal= FALSE;
OCILobDescriptor ????
  if(OCILobCreateTemporary(svchp, errhp, loc1, (ub2)0, SQLCS_IMPLICIT,
                           OCI_TEMP_BLOB, OCI_ATTR_NOCACHE, 
                           OCI_DURATION_SESSION))
  {
     (void) printf("FAILED: CreateTemporary() \n");
     return -1;
  } 
   if(OCILobCreateTemporary(svchp, errhp, loc2, (ub2)0, SQLCS_IMPLICIT,
                            OCI_TEMP_BLOB, OCI_ATTR_NOCACHE, 
                            OCI_DURATION_SESSION))
  {
     (void) printf("FAILED: CreateTemporary() \n");
     return -1;
  } 

  if (OCILobIsEqual(envhp,loc1,loc2, &is_equal))
  {
    printf ("FAILED: OCILobLocatorIsEqual call\n");
    return -1;
  }
  if(is_equal)
  {
      fprintf (stderr,"LOB loators are equal \n");
      return -1;
 
   }else
   {
      fprintf(stderr,"LOB locators are not equal \n");
   }
   if(OCILobFreeTemporary(svchp,errhp,loc1))
   {
        printf("FAILED: OCILobFreeTemporary for temp LOB #1\n");
        return -1;
   }
  if(OCILobFreeTemporary(svchp,errhp,loc2))
   {
        printf("FAILED: OCILobFreeTemporary for temp LOB #2\n");
        return -1;
   }
OCILobDescriptor free????
   return 0;
  }

C/C++ (Pro*C/C++): See If One LOB Locator for a Temporary LOB Is Equal to Another

#include <sql2oci.h>
#include <stdio.h>
#include <sqlca.h>

void Sample_Error()
{
  EXEC SQL WHENEVER SQLERROR CONTINUE;
  printf("sqlcode = %ld\n", sqlca.sqlcode);
  printf("%.*s\n", sqlca.sqlerrm.sqlerrml, sqlca.sqlerrm.sqlerrmc);
  EXEC SQL ROLLBACK WORK RELEASE;
  exit(1);
}

void seeTempLobLocatorsAreEqual_proc()
{
  OCIBlobLocator *Temp_loc1, *Temp_loc2; 
  OCIBFileLocator *Lob_loc; 
  char *Dir = "AUDIO_DIR", *Name = "Washington_audio"; 
  int Amount = 4096; 
  OCIEnv *oeh; 
  int isEqual = 0; 

  EXEC SQL WHENEVER SQLERROR DO Sample_Error(); 
  /* Allocate and Create the Temporary LOBs: */ 
  EXEC SQL ALLOCATE :Temp_loc1; 
  EXEC SQL ALLOCATE :Temp_loc2; 
  EXEC SQL LOB CREATE TEMPORARY :Temp_loc1; 
  EXEC SQL LOB CREATE TEMPORARY :Temp_loc2; 
  /* Allocate and Initialize the BFILE Locator: */ 
  EXEC SQL ALLOCATE :Lob_loc; 
  EXEC SQL LOB FILE SET :Lob_loc DIRECTORY = :Dir, FILENAME = :Name; 
  /* Opening the LOBs is Optional: */ 
  EXEC SQL LOB OPEN :Lob_loc READ ONLY; 
  EXEC SQL LOB OPEN :Temp_loc1 READ WRITE; 
  EXEC SQL LOB OPEN :Temp_loc2 READ WRITE; 
  
  /* Load a specified amount from the BFILE into one of the Temporary LOBs: */ 
  EXEC SQL LOB LOAD :Amount FROM FILE :Lob_loc INTO :Temp_loc1; 
  /* Retrieve the OCI Environment Handle: */ 
  (void) SQLEnvGet(SQL_SINGLE_RCTX, &oeh); 
  
  /* Now assign Temp_loc1 to Temp_loc2 using Embedded SQL: */ 
  EXEC SQL LOB ASSIGN :Temp_loc1 TO :Temp_loc2; 
  
  /* Determine if the Temporary LOBs are Equal: */ 
  (void) OCILobIsEqual(oeh, Temp_loc1, Temp_loc2, &isEqual); 
  
  /* This time, isEqual should be 0 (FALSE): */ 
  printf("Locators %s equal\n", isEqual ? "are" : "are not"); 
  
  /* Assign Temp_loc1 to Temp_loc2 using C pointer assignment: */ 
  Temp_loc2 = Temp_loc1; 
  
  /* Determine if the Temporary LOBs are Equal again: */ 
  (void) OCILobIsEqual(oeh, Temp_loc1, Temp_loc2, &isEqual); 
  
  /* The value of isEqual should be 1 (TRUE) in this case: */ 
  printf("Locators %s equal\n", isEqual ? "are" : "are not"); 
  
  /* Closing the LOBs is Mandatory if they have been Opened: */ 
  EXEC SQL LOB CLOSE :Lob_loc;    
  /* Note that because Temp_loc1 and Temp_loc2 are now equal, closing
     and freeing one will implicitely do the same to the other: */
  EXEC SQL LOB CLOSE :Temp_loc1;  
  EXEC SQL LOB FREE TEMPORARY :Temp_loc1;  
  /* Release resources held by the Locators: */ 
  EXEC SQL FREE :Lob_loc; 
  EXEC SQL FREE :Temp_loc1; 
}

void main()
{
  char *samp = "samp/samp";
  EXEC SQL CONNECT :samp;
  seeTempLobLocatorsAreEqual_proc();
  EXEC SQL ROLLBACK WORK RELEASE;

}