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int BlockAccess::deleteRelation(char relName[ATTR_SIZE]) { // if the relation to delete is either Relation Catalog or Attribute Catalog, // return E_NOTPERMITTED // (check if the relation names are either "RELATIONCAT" and "ATTRIBUTECAT". // you may use the following constants: RELCAT_NAME and ATTRCAT_NAME) /* reset the searchIndex of the relation catalog using RelCacheTable::resetSearchIndex() */

Question

int BlockAccess::deleteRelation(char relName[ATTR_SIZE]) { // if the relation to delete is either Relation Catalog or Attribute Catalog, // return E_NOTPERMITTED // (check if the relation names are either "RELATIONCAT" and "ATTRIBUTECAT". // you may use the following constants: RELCAT_NAME and ATTRCAT_NAME) /* reset the searchIndex of the relation catalog using RelCacheTable::resetSearchIndex() */

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Solution

It seems like you've pasted a piece of code and want me to explain it. However, you didn't ask a specific question about it. The code is written in C++ and it's a function named deleteRelation in the BlockAccess class. This function takes a character array relName of size ATTR_SIZE as an argument.

Here's a step-by-step explanation of the code:

  1. The function deleteRelation is declared which belongs to the class BlockAccess. It takes one argument, a character array relName of size ATTR_SIZE.

  2. Inside the function, there's a comment that suggests the function should return E_NOTPERMITTED if the relation to delete is either Relation Catalog or Attribute Catalog. This is indicated by checking if the relation names are either "RELATIONCAT" and "ATTRIBUTECAT". The constants RELCAT_NAME and ATTRCAT_NAME may be used for this purpose. However, the actual code to perform this operation is not provided.

  3. There's another comment that suggests resetting the searchIndex of the relation catalog using RelCacheTable::resetSearchIndex(). Again, the actual code to do this is not provided.

Please provide a specific question about this code for a more detailed explanation.

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Similar Questions

int Schema::deleteRel(char *relName) { // if the relation to delete is either Relation Catalog or Attribute Catalog, // return E_NOTPERMITTED // (check if the relation names are either "RELATIONCAT" and "ATTRIBUTECAT". // you may use the following constants: RELCAT_NAME and ATTRCAT_NAME) // get the rel-id using appropriate method of OpenRelTable class by // passing relation name as argument // if relation is opened in open relation table, return E_RELOPEN // Call BlockAccess::deleteRelation() with appropriate argument. // return the value returned by the above deleteRelation() call /* the only that should be returned from deleteRelation() is E_RELNOTEXIST. The deleteRelation call may return E_OUTOFBOUND from the call to loadBlockAndGetBufferPtr, but if your implementation so far has been correct, it should not reach that point. That error could only occur if the BlockBuffer was initialized with an invalid block number. */}

DELETE statement can delete tuples in a relation but can not remove the relation schema.

____________ is the command to purge (get rid of) all the values in the relation named TEACHES.a.REMOVE TABLE TEACHES;b.DELETE FROM TEACHES;c.DROP TABLE TEACHES;d.DELETE FROM TEACHES WHERE ID =’NULL’;e.None of the answers are correct

Which command is used to remove a relation from an SQL?Answer areaDrop tableDeletePurgeRemove

Delete¶Implement method DeleteProduct(string id). Use DeleteOne on the collection to delete the record. You will need a filter expression here to find the matching record similarly to how it was done in FindProduct(string id).Test the functionality using the web application by clicking the Delete link next to a product.

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