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ROWID index

Two indices are created by default during the table creation: the ROWID and recbyt indices.

The ROWID index, formed by a field and an associated index, holds the auto increment value generated automatically by c-tree every time a new record is added to the table.

When a table is created with ROWID support, a ROWID index is automatically created for the table. The operation of the ROWID index is transparent to the c-treeDB user. c-treeDB will automatically update the index entries. The ROWID index will not appear in the list of indexes for a table. The user cannot alter or delete the components of the ROWID index.

Functions that deal with the ROWID index are:

  • CTTable::HasRowid() - to determine if the table has ROWID support;
  • CTRecord::GetRowid() - to retrieve the ROWID for a given record;
  • CTRecord::FindRowid() - to locate and retrieve a record, given the ROWID.

By default, all c-treeDB created tables have support for the ROWID index. If, for any reason, a table should be created without support for this index, the create mode CTCREATE_NOROWID should be added in CTTable:Create() method.