first half of db lec

cst363/lec/lec13.md

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+# lec13
+
+## Lab Exercises
+
+This lecture has a lab portion in `lab/` directory.
+Directions are on `index-structures-lab.pdf` and `ordered-indexes-lab.pdf`.
+
+## Indexing
+
+We create an index based on some field, where we sort the entries in this index table.
+Each entry then contains a pointer to each record in the target table.
+Sorting the indexes allows us to search them _much faster_ than we could ever do on disk.
+
+> What about collision?
+
+Then we simply add a pointer to the index's list of associated pointers.
+
+It's important to note that indexes are tables, just like everything else in sql.