Reading data by using solidDB® SA without SQL

With solidDB^® SA, data is queried using cursors. The query data is found in a way similar to update and delete operations. A cursor is created to a specific table, variables are bound to columns of the table, and the cursor is then opened. The constraints for finding the rows for the query are set before starting the actual search. If more than one row is found, each row must be fetched separately. After all the rows are fetched, the cursor needs to be freed.

Basically, all solidDB^® SA queries use the solidDB^® optimizer in a way similar to SQL-based queries. The index selection strategy is the same as in SQL. The only exception is that the solidDB^® SA search uses ORDER BY for selecting an index. This means that an index that best fits ORDER BY is the one selected. If two indices are equally good, then the one with a smaller cost is selected. The query is optimized each time SaCursorSearch is called.

Steps	SA function(s)	Comment
1 Create a cursor	SaCursorCreate
2 Bind variables to cursor	SaCursorColInt, SACursorColStr and others for other data types
3 Open the cursor	SaCursorOpen
4 Set the search constraint for the row to be queried	SaCursorEqual, SaCursorAtleast, SaCursorAtmost
5 Start a search for the row to be queried	SaCursorSearch
6 Fetch the row(s) that match the given criteria	SaCursorNext	Perform this in a loop if necessary
7 Free the cursor	SaCursorFree

/* Bind variables to columns of test table. */
rc = SaCursorColInt(scur, "INTC", &intc);
rc = SaCursorColStr(scur, "CHARC", &str);

/* Set search constraints. */
str = "A";
rc = SaCursorAtleast(scur, "CHARC");
str = "C";
rc = SaCursorAtmost(scur, "CHARC");

/* Set ordering criteria. */
rc = SaCursorAscending(scur, "CHARC");
/* Start a search. */
rc = SaCursorSearch(scur);
/* Fetch the rows. */
for (i = 1; i <= 3; i++) {
  rc = SaCursorNext(scur);
  switch (intc) {
  case 1:
    assert(strcmp(str, "A"), == 0);
    break;
  case 2:
    assert(strcmp(str, "B”), == 0);
    break;
  case 3:
    assert(strcmp(str, "C"), == 0);
    break; }
  }