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T. Miodragovi´ c et al.
• distance between the noise source and microphone;
• measured equivalent noise level;
• spectral distribution of noise.
The database is not intended to be used only by participants of project “urbaNoise,”
but also to permit public access to reading collected data, so the third parties could
use data as input in software tools for noise mapping. It should be accessible over
Internet and should respond to standard SQL queries.
4 Database Structure
Entity–relationship (ER) diagrams are often used in design of relational database.
An ER diagram is a flowchart that illustrates the logical structure of a database by
defining its entities, their attributes and relationships. Database entity is an object
about which data are stored in the form of table. The properties of an entity are defined
by its attributes. Primary key represents an attribute or set of attributes that uniquely
identifies a particular entity. Foreign keys are attributes that define relationships
between the entities. The attributes of a foreign key in one table are the attributes of
a primary key in another table. Relationships between the entities can be “1-to-1”
or “1-to-many”. “1-to-1” relationship between two tables indicates that each record
in the first table corresponds to one, and only one, record in the second table. “1-tomany” relationship indicates that each record in the first table corresponds to one or
more records in the second table, but each record in the second table corresponds to
only one record in the first table.
The entity–relationship diagram of the database structure is shown in Fig. 1. A
noise source is represented by the table source, which contains the following attributes
(columns):
• SourceID—the primary key of the table;
• source_name—the name of the source;
• source_description—the textual description of the noise source;
• distance—microphone distance from the noise source during measurement;
• noise_level—measured equivalent A-weighted noise level
The table noise_spectrum is linked by “1 − to − 1” relationship to the table source
by the key source_SourceID. This table contains information about third octave noise
spectrum, which is described by sound level for each third octave frequency range,
as shown in Fig. 1.
T. Miodragovi´ c et al.
• distance between the noise source and microphone;
• measured equivalent noise level;
• spectral distribution of noise.
The database is not intended to be used only by participants of project “urbaNoise,”
but also to permit public access to reading collected data, so the third parties could
use data as input in software tools for noise mapping. It should be accessible over
Internet and should respond to standard SQL queries.
4 Database Structure
Entity–relationship (ER) diagrams are often used in design of relational database.
An ER diagram is a flowchart that illustrates the logical structure of a database by
defining its entities, their attributes and relationships. Database entity is an object
about which data are stored in the form of table. The properties of an entity are defined
by its attributes. Primary key represents an attribute or set of attributes that uniquely
identifies a particular entity. Foreign keys are attributes that define relationships
between the entities. The attributes of a foreign key in one table are the attributes of
a primary key in another table. Relationships between the entities can be “1-to-1”
or “1-to-many”. “1-to-1” relationship between two tables indicates that each record
in the first table corresponds to one, and only one, record in the second table. “1-tomany” relationship indicates that each record in the first table corresponds to one or
more records in the second table, but each record in the second table corresponds to
only one record in the first table.
The entity–relationship diagram of the database structure is shown in Fig. 1. A
noise source is represented by the table source, which contains the following attributes
(columns):
• SourceID—the primary key of the table;
• source_name—the name of the source;
• source_description—the textual description of the noise source;
• distance—microphone distance from the noise source during measurement;
• noise_level—measured equivalent A-weighted noise level
The table noise_spectrum is linked by “1 − to − 1” relationship to the table source
by the key source_SourceID. This table contains information about third octave noise
spectrum, which is described by sound level for each third octave frequency range,
as shown in Fig. 1.