Data Types

Turso uses the same dynamic type system as SQLite, where values have types but columns do not enforce a single type (unless using STRICT tables). Every value stored in Turso belongs to one of five storage classes.

Storage Classes

SELECT typeof(NULL);       -- 'null'
SELECT typeof(42);         -- 'integer'
SELECT typeof(3.14);       -- 'real'
SELECT typeof('hello');    -- 'text'
SELECT typeof(x'CAFE');    -- 'blob'

Type Affinity

When a column is declared with a type name, Turso assigns a type affinity to that column. Type affinity is a recommendation for how to store values, not a strict constraint (unless using STRICT tables). Turso uses the same affinity rules as SQLite.

Affinity Determination Rules

The type affinity of a column is determined by the declared type name, using these rules applied in order:

-- Type affinity is a suggestion, not a constraint
CREATE TABLE flexible (
    id INTEGER,
    name TEXT,
    data BLOB
);

-- This works - TEXT value in an INTEGER column
INSERT INTO flexible VALUES ('not a number', 42, 'text in blob');
SELECT typeof(id), typeof(name), typeof(data) FROM flexible;
-- 'text', 'integer', 'text'

Type Conversions

When a value is inserted into a column, Turso attempts to convert the value to the column's affinity:

• INTEGER affinity: If the value is TEXT or REAL that looks like an integer, Turso converts the value to INTEGER
• REAL affinity: If the value is TEXT that looks like a number, Turso converts to REAL. If the value is an integer, Turso converts to REAL
• NUMERIC affinity: Turso tries INTEGER first, then REAL, then keeps as TEXT
• TEXT affinity: Integer and REAL values are converted to their text representation
• BLOB affinity: No conversion is attempted

STRICT Tables

STRICT tables enforce type checking at the storage layer. Every value inserted into a STRICT table must match the declared column type or be convertible to the column type.

CREATE TABLE users (
    id INTEGER PRIMARY KEY,
    name TEXT NOT NULL,
    age INTEGER,
    score REAL
) STRICT;

-- This works - values match declared types
INSERT INTO users VALUES (1, 'Alice', 30, 95.5);

-- This fails - 'thirty' cannot be converted to INTEGER
INSERT INTO users VALUES (2, 'Bob', 'thirty', 80.0);
-- Error: cannot store TEXT value in INTEGER column

Allowed Types in STRICT Tables

STRICT tables only allow these base type names:

Custom Types

Custom types let you define how values are encoded before storage and decoded when read, enforce domain constraints at the storage layer, attach operators, and provide defaults. Custom types are declared with the CREATE TYPE statement.

-- A type that stores monetary values as cents
CREATE TYPE cents BASE integer
    ENCODE value * 100
    DECODE value / 100;

CREATE TABLE prices (
    id INTEGER PRIMARY KEY,
    amount cents
) STRICT;

INSERT INTO prices VALUES (1, 42);
SELECT amount FROM prices;
-- 42  (stored on disk as 4200)

Built-in Custom Types

Turso provides several built-in custom types available in STRICT tables:

CREATE TABLE events (
    id uuid PRIMARY KEY,
    name varchar(100),
    event_date date,
    is_active boolean DEFAULT 1,
    metadata json
) STRICT;

INSERT INTO events VALUES (
    uuid4(),
    'Product Launch',
    '2025-03-15',
    1,
    '{"venue": "online"}'
);

For the full custom types reference including ENCODE/DECODE, operators, parametric types, and validation, see CREATE TYPE.

Inspecting Types

List all available types (built-in and custom):

PRAGMA list_types;

All types are also available through the sqlite_turso_types virtual table:

SELECT name, sql FROM sqlite_turso_types;

Comparison and Sorting

Turso uses the same comparison rules as SQLite. Values of different storage classes are ordered as:

NULL < INTEGER/REAL < TEXT < BLOB

• NULL values are considered less than any other value
• INTEGER and REAL values are compared numerically
• TEXT values are compared using the column's collation sequence (default: BINARY)
• BLOB values are compared using memcmp()

SELECT 1 < 2;          -- 1 (true)
SELECT 'abc' < 'abd';  -- 1 (true)
SELECT 1 < '2';        -- 1 (true, numeric < text)
SELECT NULL < 1;        -- NULL (any comparison with NULL yields NULL)
SELECT NULL IS NULL;    -- 1 (use IS to test for NULL)

See Also

• CREATE TABLE for column definitions and constraints
• CREATE TYPE for custom type definitions
• Expressions for CAST expressions and type conversions
• Compatibility for differences from SQLite