Value type declarations

Value types appear in graph definitions, session declarations and parser-only casts/type predicates. The parser’s type vocabulary is broader than the executable value representation.

Family	Grammar examples
Boolean	BOOLEAN, BOOL
Integers and numerics	INTEGER, BIG INTEGER, INT(64), DECIMAL(8,2), FLOAT(24,2), DOUBLE
Characters and bytes	STRING, VARCHAR(64), CHAR(16), BYTES(16), VARBINARY(512)
Temporal	DATE, TIME, TIMESTAMP, LOCAL TIME, TIME WITH TIME ZONE
Lists and arrays	LIST<STRING>, STRING LIST, INTEGER ARRAY[3]
Records	RECORD, RECORD {name STRING}, {name STRING}
Dynamic unions	INTEGER | STRING, ANY<STRING | INTEGER>
Graph values	PATH, ANY NODE, EDGE, GRAPH, BINDING TABLE
General property values	PROPERTY VALUE

Declarations can apply NOT NULL. A union accepts null only when its members permit null; combining exclusively non-null types does not create a nullable union.

SESSION SET VALUE $limit INTEGER NOT NULL = 10;
SESSION SET VALUE $names LIST<STRING> = ['Alice', 'Bob'];
RETURN $limit AS limit, $names AS names;

Query scalars currently normalize integer and approximate numeric values to Int64/Float64 after supported declaration validation. Decimal literals are f64, not an exact decimal implementation. A DECIMAL or NUMERIC session parameter accepts an integer or finite decimal literal that fits the declared precision and scale (DECIMAL(p) means scale 0), then reads back as Float64. CHAR(n) limits a character string to n characters, the same maximum VARCHAR(n) and STRING(n) enforce; a shorter string is valid. Temporal values, arbitrary unions and structured references do not automatically become executable query scalars because their types parse.

Graph definitions preserve constraints including approximate-numeric scale. Unsupported nesting is rejected before durable publication so a committed definition remains recoverable.