Inserting rows with an MR_COUNTER column
While data is inserted in a multi-region table with an MR_COUNTER column, the system generates a default value of zero for the MR_COUNTER column value in the following two cases.
-
When the keyword
DEFAULTis used in the INSERT clause for the MR_COUNTER column. -
When the MR_COUNTER column is skipped in the INSERT clause.
Specifying DEFAULT clause while inserting data into an MR_COUNTER column
Example 1 - Insert a row to a multi-region table using the DEFAULT clause
Create a multi-region table in DEN and LON regions with an MR_COUNTER:
CREATE Table myTable( name STRING,
count INTEGER AS MR_COUNTER,
PRIMARY KEY(name)) IN REGIONS DEN,LON
Insert a row to the table by specifying the DEFAULT clause to the counter:
INSERT INTO myTable VALUES ("Bob", DEFAULT)
Fetch the counter value:
SELECT * FROM myTable
Output:
{"name":"Bob","count":0}
Skipping the MR_COUNTER column while inserting data into a multi-region table
Example 2 - Insert a row to a multi-region table without specifying a value to the MR_COUNTER
Create a multi-region table in DEN and LON regions with an MR_COUNTER:
CREATE Table myTable( name STRING,
count INTEGER AS MR_COUNTER,
PRIMARY KEY(name)) IN REGIONS DEN,LON
Insert a row to the table by specifying the column names, without specifying the counter or supplying any value to it:
INSERT INTO myTable(name) VALUES ("Chris')
Fetch the table data. Notice that the system automatically inserts a zero value to the counter.
SELECT * FROM myTable
Output:
{"name":"Chris","count":0}
Error when MR_COUNTER column is not skipped and no DEFAULT clause is given
While inserting all column values to a row, you must specify the DEFAULT clause for the MR_COUNTER column. Else, the system displays an error.
Example 3 - Insert all columns in a row without specifying a value to the MR_COUNTER
Create a multi-region table in DEN and LON regions with an MR_COUNTER:
CREATE Table myTable( name STRING,
count INTEGER AS MR_COUNTER,
PRIMARY KEY(name)) IN REGIONS DEN,LON
Insert all the columns in a row. Notice that you don’t supply a DEFAULT value to the counter.
INSERT INTO myTable VALUES ("Chris")
Output:
Error handling command execute 'INSERT INTO myTable VALUES ("Chris")':
Error: at (1, 0) The number of VALUES expressions is not equal to the number of table columns
You cannot insert values into an MR_COUNTER column explicitly. A DEFAULT construct must always be used or the MR_COUNTER column should be skipped in the INSERT clause. If you try to insert values into the MR_COUNTER column using the INSERT clause or using API, an error is thrown as shown below.
Example 4 - Insert a row to a multi-region table by specifying a value other than DEFAULT to the MR_COUNTER
CREATE Table myTable ( name STRING,
count INTEGER AS MR_COUNTER,
PRIMARY KEY(name)) IN REGIONS DEN
INSERT INTO myTable VALUES("Tom",0)'
Output:
Error handling command execute 'INSERT INTO myTable VALUES("Tom",0)': Error: at (1, 38) MRCounter column must use DEFAULT construct.
Inserting rows into a JSON column having MR_COUNTER data type
When inserting a row into the multi-region table with a JSON MR_COUNTER, you must supply a value zero to the MR_COUNTER.
Note:
- The system initially assigns a value of zero to all MR_COUNTER data types even if you explicitly supply a non-zero value. This also holds good when you try to provide a value that is not an INTEGER or LONG or NUMBER.
- You can't supply the keyword DEFAULT while inserting a JSON MR_COUNTER.
- The system will return an error if you try to insert data into an MR table without supplying a value to the declared JSON MR_COUNTER field or using the keyword DEFAULT.
Example 5 - Insert data into multi-region table with a JSON MR_COUNTER
INSERT INTO demoJSONMR VALUES ("Anna",
{
"id" : 1,
"counter" : 0,
"person" : {
"age" : 10,
"count" : 0,
"number" : 100
}
}
)
SELECT * FROM demoJSONMR
Output:
{"name":"Anna","jsonWithCounter":{"id" : 1,"counter":0,
"person":{"age":10,"count":0,"number":100}
}
}