lsst.dax.apdb gd2a12a3803+f8351bc914
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Public Member Functions | |
__init__ (self, sqlalchemy.engine.Engine engine, sqlalchemy.schema.Table|None table) | |
str|None | get (self, str key, str|None default=None) |
None | set (self, str key, str value, *bool force=False) |
bool | delete (self, str key) |
Generator[tuple[str, str], None, None] | items (self) |
bool | empty (self) |
bool | table_exists (self) |
Protected Attributes | |
_engine | |
_table | |
Implementation of `ApdbMetadata` for SQL backend. Parameters ---------- engine : `sqlalchemy.engine.Engine` Database access engine. table : `sqlalchemy.schema.Table` or `None` Database table holding metadata. If table does not exists then `None` should be specified.
bool lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.delete | ( | self, | |
str | key ) |
Delete metadata record. Parameters ---------- key : `str` Metadata key, arbitrary non-empty string. Returns ------- existed : `bool` `True` is returned if attribute existed before it was deleted.
Reimplemented from lsst.dax.apdb.apdbMetadata.ApdbMetadata.
bool lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.empty | ( | self | ) |
Check whether attributes set is empty. Returns ------- empty : `bool` `True` if there are no any attributes defined. `True` is also returned if metadata table is missing.
Reimplemented from lsst.dax.apdb.apdbMetadata.ApdbMetadata.
str | None lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.get | ( | self, | |
str | key, | ||
str | None | default = None ) |
Retrieve value of a given metadata record. Parameters ---------- key : `str` Metadata key, arbitrary non-empty string. default : `str`, optional Default value returned when key does not exist, can be string or `None`. Returns ------- value : `str` or `None` Metadata value, if key does not exist then ``default`` is returned.
Reimplemented from lsst.dax.apdb.apdbMetadata.ApdbMetadata.
Generator[tuple[str, str], None, None] lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.items | ( | self | ) |
Iterate over records and yield their keys and values. Yields ------ key : `str` Metadata key. value : `str` Corresponding metadata value.
Reimplemented from lsst.dax.apdb.apdbMetadata.ApdbMetadata.
None lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.set | ( | self, | |
str | key, | ||
str | value, | ||
*bool | force = False ) |
Set value for a given metadata record. Parameters ---------- key : `str` Metadata key, arbitrary non-empty string. value : `str` New metadata value, an arbitrary string. Due to deficiencies of some database engines we are not allowing empty strings to be stored in the database, and ``value`` cannot be an empty string. force : `bool`, optional Controls handling of existing metadata. With default `False` value an exception is raised if ``key`` already exists, if `True` is passed then value of the existing key will be updated. Raises ------ KeyError Raised if key already exists but ``force`` option is false. ValueError Raised if key or value parameters are empty.
Reimplemented from lsst.dax.apdb.apdbMetadata.ApdbMetadata.
bool lsst.dax.apdb.apdbMetadataSql.ApdbMetadataSql.table_exists | ( | self | ) |
Return `True` if metadata table exists.