Static lookup table : lookup table for query and retrieval operations only
Dynamic lookup table : after querying, you also need to insert data elements whose query results are not in the lookup table into the lookup table; or delete the data elements whose query results are in the lookup table from the lookup table;
In short, the structure of the dynamic lookup table can be modified or changed at any time. The table structure itself is dynamically generated during the search process . Generally speaking, the chain structure has this feature, such as binary search trees, three trees, etc. In addition, Hash lookup based on sequential storage should also be considered as a dynamic lookup table; and the structure of a static lookup table is no longer allowed to change after it is generated once , just like using a binary search on an ordered array.