changes made to rows in the database after the row was fetched aren't visible through the cursor. Forward-only cursors are dynamic by default, meaning that all changes are detected as the current row is processed. This provides faster cursor opening and enables the result set to display updat...
SQL Server provides the@@FETCHSTATUSfunction that returns the status of the last cursorFETCHstatement executed against the cursor;If@@FETCHSTATUSreturns 0, meaning theFETCHstatement was successful. You can use theWHILEstatement to fetch all rows from the cursor as shown in the following code: WHIL...
changes made to rows in the database after the row was fetched aren't visible through the cursor. Forward-only cursors are dynamic by default, meaning that all changes are detected as the current row is processed. This provides faster cursor opening and enables the result set to display updat...
Causes statements that may differ in some literals, but are otherwise identical, to share a cursor, unless the literals affect either the meaning of the statement or the degree to which the plan is optimized. (3)EXACT Only allows statements with identical text to share the same cursor. --只...
SQL is a set-based language, meaning operations are completed on all or rows of the result. However, there are times, when you want to do operation on a row by row basis. This is where cursors come in to play. What is a Database Cursor? A database cursor can be thought of as a...
Function has_emp(p_empno in varchar2) Return BOOLEAN Is Retval boolean; l_dummy number; csr_emp sys_refcursor; Begin Open csr_emp For 'Select 1 from ps_employee where empno = :1' Using p_empno; Fetch csr_emp Into l_dummy;
Specifies that the result table of the cursor is dynamic, meaning that the size of the result table might change after the cursor is opened as rows are inserted into or deleted from the underlying table, and the order of the rows might change. Rows that are inserted, deleted, or updated ...
T-SQL and SQL Server are designed to work best with sets of data, not one row at a time. Jeff Moden famously termed this type of processing RBAR (pronounced, ree-bar), meaning Row By Agonizing Row. However, if a cursor must be used, then use a cursor with the least cost....
ConnectionPtr pConnection =NULL; HRESULT hr = S_OK;_bstr_tstrCnn("Provider='sqloledb';Data Source='MySqlServer';""Initial Catalog='pubs';Integrated Security='SSPI';");try{// Open a connectionTESTHR(pConnection.CreateInstance(__uuidof(Connection))); hr = ...
Meaning Before start The block cursor is positioned before the start of the result set. If the first row of the new rowset is before the start of the result set, SQLFetchScroll() returns SQL_NO_DATA. After end The block cursor is positioned after the end of the result set. If the ...