CODEWITHSUNDEEP
pythonsqlalchemy
Thomas Browne
Thomas Browne

Reputation: 24928

How do I check which fields have indices in an SQLAlchemy table or class?

Here's a table definitition using SQLAlchemy declarative_base:

t_measures_voyage_crude = Table(
    'measures_voyage_crude', metadata,
    Column('tanker', String(255)),
    Column('load_point', Text),
    Column('load_port', String(255)),
    Column('load_country', NullType),
    Column('load_region', String(255)),
    Column('date_depart', Date),
    Column('offtake_point', Text),
    Column('offtake_port', String(255)),
    Column('offtake_country', NullType),
    Column('offtake_region', String(255)),
    Column('date_arrive', Date),
    Column('grade', Text),
    Column('bbls', BigInteger),
    Column('row_num', Integer, index=True),
    Column('date_num', Integer, index=True),
    Column('stat_num', Integer, index=True),
    schema='numbergo'
)

It has three indexed fields, but if I have the table object in a variable, how do I list these columns that have indices?

Similarly for a class, say this one:

class MasterBpd(Base):
    __tablename__ = 'master_bpd'
    __table_args__ = {'schema': 'numbergo'}

    date = Column(Date, primary_key=True)
    bpd_imp_yr = Column(Integer)
    bpd_imp_mo = Column(Integer)
    bpd_imp_wk = Column(Integer)
    bpd_dom_yr = Column(Integer)
    bpd_dom_mo = Column(Integer)
    bpd_dom_wk = Column(Integer)
    row_num = Column(BigInteger, nullable=False, index=True)
    date_num = Column(BigInteger, nullable=False, index=True)

How do I check programmatically which fields have indices, and which is the primary key?

Upvotes: 1

Views: 1372

Answers (1)

An Le
An Le

Reputation: 43

for col in MasterBpd.__table__.columns:
   print(col.index) # True if this field has index, None otherwise
   print(col.primary_key) # True if is primary key, False otherwise

Upvotes: 2

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