Managing tag meta (tag name)
Concept of tag meta
The tag meta represents the name and additional information of an arbitrary tag stored in the Machbase.
That is, if there are three tags existing in a specific apparatus, an arbitrary name representing the tag and related additional information are required, which are all referred to as meta information of the tag.
This tag meta should specify at least a name and, if necessary, specify various data types for the device.
Tag meta with tag name only
Creation of tag meta
Below is the command to create the TAG table where the most basic tag meta is created.
create tag table TAG (name varchar(20) primary key, time datetime basetime, value double summarized);
Mach> desc tag;
[ COLUMN ]
----------------------------------------------------------------
NAME TYPE LENGTH
----------------------------------------------------------------
NAME varchar 20
TIME datetime 31
VALUE double 17The above is the basic TAG table creation, and there is no separate information about the tag meta.
In this case, the tag meta has only basic information of VARCHAR (20).
Input of tag meta
Now, let’s insert one piece of tag information named TAG1.
Mach> insert into tag metadata values ('TAG_0001');
1 row(s) inserted.Through the above query, we created one tag named TAG_0001.
Output of tag meta
Machbase provides a special table _tag_meta for identifying the information of the input tag meta.
Therefore, the user can confirm the information of all the tags input in the Machbase through the following query.
Mach> select * from _tag_meta;
ID NAME
----------------------------------------------
1 TAG_0001
[1] row(s) selected.The ID is automatically assigned as an internally managed value.
Modifying tag meta
Machbase allows you to modify the input tag meta information. The name can be modified as follows.
Mach> update tag metadata set name = 'NEW_0001' where NAME = 'TAG_0001';
1 row(s) updated.
Mach> select * from _tag_meta;
ID NAME
----------------------------------------------
1 NEW_0001
[1] row(s) selected.You can see that the name has been changed from TAG_0001 to NEW_0001 as above.
Deleting tag meta
You can delete the actual tag meta information as shown below.
Mach> delete from tag metadata where name = 'NEW_0001';
1 row(s) deleted.
Mach> select * from _tag_meta;
ID NAME
----------------------------------------------
[0] row(s) selected.However, it should be noted that tag meta can be deleted when the actual data of the tag dosen’t refer to the corresponding tag meta.
Tag meta with additional information
Creation of tag meta
Below, we will add 16 bit integer, time, and IPv4 information to the tag meta information.
Note that once you have created a tag meta, you can modify the value except the structure.
create tag table TAG (name varchar(20) primary key, time datetime basetime, value double summarized)
metadata (type short, create_date datetime, srcip ipv4) ;
Mach> desc tag;
[ COLUMN ]
----------------------------------------------------------------
NAME TYPE LENGTH
----------------------------------------------------------------
NAME varchar 20
TIME datetime 31
VALUE double 17
[ META-COLUMN ]
----------------------------------------------------------------
NAME TYPE LENGTH
----------------------------------------------------------------
TYPE short 6
CREATE_DATE datetime 31
SRCIP ipv4 15 Input of tag meta
You can check the information by typing the following with the additional information other than the name.
Mach> insert into tag metadata(name) values ('TAG_0001');
1 row(s) inserted.
Mach> select * from _tag_meta;
ID NAME TYPE CREATE_DATE SRCIP
-------------------------------------------------------------------------------------------------------------
1 TAG_0001 NULL NULL NULL
[1] row(s) selected.Like above, NULL is inserted except NAME column.
Now let’s add more information as shown below.
Mach> insert into tag metadata values ('TAG_0002', 99, '2010-01-01', '1.1.1.1');
1 row(s) inserted.
Mach> select * from _tag_meta;
ID NAME TYPE CREATE_DATE SRCIP
-------------------------------------------------------------------------------------------------------------
1 TAG_0001 NULL NULL NULL
2 TAG_0002 99 2010-01-01 00:00:00 000:000:000 1.1.1.1
[2] row(s) selected.Additional Information made each tag meta can be given a wealth of information.
Modifying tag meta
Now let’s change the type of TAG_0001 from NULL to 11.
Mach> update tag metadata set type = 11 where name = 'TAG_0001';
1 row(s) updated.
Mach> select * from _tag_meta;
ID NAME TYPE CREATE_DATE SRCIP
-------------------------------------------------------------------------------------------------------------
2 TAG_0002 99 2010-01-01 00:00:00 000:000:000 1.1.1.1
1 TAG_0001 11 NULL NULL
[2] row(s) selected.You can modify the values of all fields through the UPDATE statement.
However, it is a common constraint that NAME must be specified in the WHERE clause.
Tag meta lookup via RESTful API
Get all tag lists
Below is an example of getting a list of all the tags in Machbase.
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/list"
{"ErrorCode": 0,
"ErrorMessage": "",
"Data": [{"NAME": "TAG_0001"},
{"NAME": "TAG_0002"}]}
Host:~$Get the time range of a specific tag
Below is an example of obtaining the minimum and maximum time range of the data that the desired tag has.
This feature is very useful when charting specific tags.
Syntax
{MWA URL}/machiot-rest-api/tags/range/ ## Time Range of whole DB
{MWA URL}/machiot-rest-api/tags/range/{TagName} ## Time Range of a specific TagGetting time range of all tags
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/range/"
{"ErrorCode": 0,
"ErrorMessage": "",
"Data": [{"MAX": "2018-02-10 10:00:00 000:000:000", "MIN": "2018-01-01 01:00:00 000:000:000"}]}
Getting Time range of a specific tag
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/range/TAG_0001"
{"ErrorCode": 0, "ErrorMessage": "", "Data": [{"MAX": "2018-01-10 10:00:00 000:000:000", "MIN": "2018-01-01 01:00:00 000:000:000"}]}
Host:~$
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/range/TAG_0002"
{"ErrorCode": 0, "ErrorMessage": "", "Data": [{"MAX": "2018-02-10 10:00:00 000:000:000", "MIN": "2018-02-01 01:00:00 000:000:000"}]}Getting Time range of a specific tag
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/range/TAG_0001"
{"ErrorCode": 0, "ErrorMessage": "", "Data": [{"MAX": "2018-01-10 10:00:00 000:000:000", "MIN": "2018-01-01 01:00:00 000:000:000"}]}
Host:~$
Host:~$ curl -G "http://192.168.0.148:5001/machiot-rest-api/tags/range/TAG_0002"
{"ErrorCode": 0, "ErrorMessage": "", "Data": [{"MAX": "2018-02-10 10:00:00 000:000:000", "MIN": "2018-02-01 01:00:00 000:000:000"}]}