Miscellaneous Notes
Table of Contents

How it works, helpful hints

Tools you can use
If you haven't already, I recommend using my Euphoria Database Browser (EDB). It runs on Windows. Check out my web page or the RDS archives for downloads and updates.

Speed
EuSQL is not extremely fast relative to commercial databases, however, there are some things you can do to speed up operations (meanwhile, I'll work on optimizing everything).

• Create an index on fields that are part of joins. When an index exists, EuSQL doesn't have to search the entire table to find the correct records. An index will slow update and insert operations, but increase SELECT queries.
• Use WHERE clauses, especially when joining two tables. In conjunction with an index or two EuSQL can avoid loading and looking at lots of records.

How it works
EuSQL needs to have an extra table, named "TABLEDEF" created in the database it is to use. This stores the structures of records in your tables. This is automatically created when you use create_db. It will also create the table "INDEXDEF", which is used to store indices created on tables.

The keys [of TABLEDEF] are the names of the tables, and the first field contains a sequence which describes the structure and field names for each table. Each field is described a sequence with two elements:

1. The field name
2. The contents/subfields

The contents of the field could be described by either an empty sequence, or by one or more field names. This way, we preserve the flexibility of deeply nested sequences, while making it easy to use the data.

Other fields [in TABLEDEF] keep track of field datatypes and indices for each table.

Example: Suppose table MAIL contains information about people on a mailing list, where the records have the structure (the first field is actually the table/EDS key, which can also be composed of multiple subfields):

{
  { "ID",   {} }
  { "Name",
        {
         {"First", {}},
         {"Last",  {}},
        }
  },
  { "Address",
          {
           {"Street", {}},
           {"City",   {}},
           {"State",  {}},
           {"ZIP",    {}}
          }
  }
}

First Name :  "name.first"
    Street :  "address.street"
   Address :  "address"
          -- actually a sequence:
          -- { Address.Street, Address.City, Address.State, Address.ZIP }
      etc.