QuestDB introduces a specific data type called symbol. It is a data structure used to store repetitive strings as a table of integers and corresponding string values.

Advantages

• Reduced complexity of database schemas by removing the need for explicit extra tables and joins.
• Transparent to the user: exact same behaviour as if the table was storing string values, without the burden of actually doing so.
• Greatly improved query performance (comparing and writing int instead of string).
• Greatly improved storage efficiency (storing int instead of string).

Usage

To declare a column as SYMBOL please refer to the CREATE TABLE section. To create an INDEX on SYMBOL, please refer to the index section.

Properties

• Symbol tables are stored separately from column data.
• Q conversion from string to int and vice-versa when reading or writing data.
• symbol supports indexes.
• For greater speed, symbol can be stored in the heap.