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type_bridge.migration.utils

utils

Shared utilities for schema operations.

type_exists 

type_exists(db, type_name)

Check if a type exists in the database schema.

Uses a simple query to check if the type name is valid in the schema. If the type doesn't exist, the query will raise an error.

Parameters:

Name Type Description Default
db Database

Database connection

 required
type_name str

Name of the type to check (entity, relation, or attribute)

 required

Returns:

Type Description
bool

True if type exists in schema, False otherwise
Example

type_exists(db, "person") True type_exists(db, "nonexistent") False

Source code in type_bridge/migration/utils.py 
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def type_exists(db: "Database", type_name: str) -> bool:
    """Check if a type exists in the database schema.

    Uses a simple query to check if the type name is valid in the schema.
    If the type doesn't exist, the query will raise an error.

    Args:
        db: Database connection
        type_name: Name of the type to check (entity, relation, or attribute)

    Returns:
        True if type exists in schema, False otherwise

    Example:
        >>> type_exists(db, "person")
        True
        >>> type_exists(db, "nonexistent")
        False
    """
    query = f"""
    match $t isa {type_name};
    fetch {{ $t.* }};
    """

    try:
        with db.transaction("read") as tx:
            # If type exists, query succeeds (even with 0 results)
            # If type doesn't exist, query raises an error
            list(tx.execute(query))
            return True
    except Exception:
        return False