Boolean Search Tutorial¶

Boolean search strings consist of a parameter-operand-value combination (e.g., a > 5), where

• parameter is the variable name,
• operand must be ==, =, !=, <, <=, >=, or >, and
  • == finds exact matches whereas = finds elements that contain the value.
• value can be a float, integer, or string.
  • Strings with spaces must be enclosed in quotes.
  • * acts a wildcard.

These paramter-operand-value combinations can be joined with the boolean operands (in order of descending precedence):

1. not
2. and
3. or

and grouped with parentheses (). For example,:

a = 5 or b = 7 and not c = 7

is equivalent to:

a = 5 or (b = 7 and (not c = 7))

In MaNGA, parameter names have hierarchical dotted field names, and are structured as schema.table.parameter, e.g. mangadatadb.cube.plateifu. If a parameter name only exists in one column in one database table, it is considered unique. Most parameters are unique can be specified using only their parameter name.

# Redshift (z) is a unique parameter name
filter  = 'z < 0.1'

# Plateifu (plateifu) is unique
filter = 'plateifu == 8485-1901'

Some parameters are not unique. In this case, you must go one level up and specify the table name as well.

# RA, Dec are not unique parameter names
filter = 'ra > 180'

query = Query(searchfilter=filter)
MarvinError: Could not set parameters. Multiple entries found for key.  Be more specific: 'ra matches multiple parameters in the lookup table: mangasampledb.nsa.ra, mangadatadb.cube.ra'.

# Correct filter
filter = 'cube.ra > 180'

# Filter string
filter = "nsa.z < 0.012 and ifu.name = 19*"
# Converts to
and_(nsa.z<0.012, ifu.name=19*)
# SQL syntax
mangasampledb.nsa.z < 0.012 AND lower(mangadatadb.ifudesign.name) LIKE lower('19%')

# Filter string
filter = 'cube.plate < 8000 and ifu.name = 19 or not (nsa.z > 0.1 or not cube.ra > 225.)'
# Converts to
or_(and_(cube.plate<8000, ifu.name=19), not_(or_(nsa.z>0.1, not_(cube.ra>225.))))
# SQL syntax
mangadatadb.cube.plate < 8000 AND lower(mangadatadb.ifudesign.name) LIKE lower(('%' || '19' || '%'))
OR NOT (mangasampledb.nsa.z > 0.1 OR mangadatadb.cube.ra <= 225.0)