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Constructs a DataFrame representing the database table accessible via JDBC URL url. Partitions of the table are retrieved in parallel if either column or predicates is specified. If both column and predicates are specified, column takes precedence.
Syntax
jdbc(url, table, column=None, lowerBound=None, upperBound=None,
numPartitions=None, predicates=None, properties=None)
Parameters
| Parameter | Type | Description |
|---|---|---|
url |
str | The JDBC URL of the form jdbc:subprotocol:subname. |
table |
str | The name of the table in the external database. |
column |
str, optional | The column to use for partitioning (alias for the partitionColumn option). Requires lowerBound, upperBound, and numPartitions. |
lowerBound |
int or str, optional | The minimum value of column for partitioning. Required when column is specified. |
upperBound |
int or str, optional | The maximum value of column for partitioning. Required when column is specified. |
numPartitions |
int, optional | The number of partitions. Required when column is specified. |
predicates |
list, optional | A list of WHERE clause expressions, each defining one partition of the DataFrame. Ignored if column is specified. |
properties |
dict, optional | JDBC connection arguments, typically including 'user' and 'password'. For example, {'user': 'SYSTEM', 'password': 'mypassword'}. |
Returns
DataFrame
Notes
Avoid creating too many partitions in parallel on a large cluster, as this can crash external database systems.