CASSANDRA CQL3 : Set value to entire column
For my Cassandra Database, I need to set a value in column for all rows in my table.
I see in SQL, we can do :
UPDATE table SET column1= XXX;
but in CQL (in cqlsh), It doesn't work ! I don't want to update row by row until 9500 rows.
Do you have any suggestion ?
Thank you :)
As you are finding out, CQL != SQL. There is no way to do what you're asking in CQL, short of iterating through each row in your table.
Robert's suggestion about redefining
column1 to be a static column may help. But static columns are tied to their partition key, so you would still need to specify that:
aploetz@cqlsh:stackoverflow2> UPDATE t SET s='XXX' WHERE k='k';
Also, it sounds like you only want to be able to set a column value for all rows. A static column won't work for you if you want that column value to be different for CQL rows within a partition (from the example in the DataStax docs):
aploetz@cqlsh:stackoverflow2> INSERT INTO t (k, s, i) VALUES ('k', 'I''m shared', 0); aploetz@cqlsh:stackoverflow2> INSERT INTO t (k, s, i) VALUES ('k', 'I''m still shared', 1); aploetz@cqlsh:stackoverflow2> SELECT * FROM t; k | i | s ---+---+------------------ k | 0 | I'm still shared k | 1 | I'm still shared (2 rows)
Note that the value of column
s is the same across all CQL rows under partition key
k. Just so you understand how that works.
UPDATE, UPDATE writes one or more column values to a row in a Cassandra table. a counter column. You can set a default TTL for an entire table by setting the table's Just a quick note on static columns, if you create some cql rows using clustered columns and don't provide a value for a static column, then selecting the row key with the (null) static column won't return any rows.
You can use update query with IN clause instead of executing 9500 query. At first select primary_key from your table and then copy values to this query:
UPDATE table SET column1 = XXX WHERE primary_key IN (p1, p2, p3, ...);
Set column, Insert data into the set, enclosing values in curly brackets. Set values must be unique, because no order is defined in a set internally. cqlsh>INSERT INTO Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. CASSANDRA CQL3 : Set value to entire column. Hot
I just added a new column to a table (+60000 rows), and I looked the way to initialize all the values of the column with something (not null), and I found nothing. Is not the same asked here, but if you drop and add the column my solution will solve it. So, this is what I did:
cqlsh> COPY tablename (primary_key, newcolumn) TO 'FILE.txt'
FILE.TXT on notepad++ and press Ctrl+H (Replace option), and replace all the
\r\n with 'something\r\n'
cqlsh> COPY tablename (primary_key, newcolumn) FROM 'FILE.txt'
Note1: You should be carefull if you primary_key contains
Note2: May be in your SO the lines doesn't ends with
Cassandra - Update Data, Cassandra - Update Data - UPDATE is the command used to update data in a table. UPDATE <tablename> SET <column name> = <new value> <column name> You can execute CQL queries using the execute() method of Session class. You can use Cassandra's counter columns data type. Keep in mind you cannot mix counter columns with non-counter columns in the same column family if the non-counter columns are not part of the composite PRIMARY KEY. So you have to separate the counters into another column family, say reviews_counts.
Cassandra Query Language(CQL): Insert Into, Update, Delete , Command 'Insert into' writes data in Cassandra columns in row form. Column values are changed in 'Set' clause while data is filtered with 'Where' Command 'Delete' removes an entire row or some columns from the table During the creation of a table, like in SQL we have DEFAULT to insert a defualt value for a column. type tinyint(1) NOT NULL DEFAULT '0'. Is there anything to achieve the same in Cassandra .
CQL, CQL v3 offers a model very close to SQL in the sense that data is put in tables For instance, the last column definition in a CREATE TABLE statement is 'some string value' $$double-dollar string can contain single ' quotes$$ Custom strategy can be provided by specifying the full class name as a string constant. The first tuple element is the column name, the second tuple element is the column value. This seems to be the most simple/accurate representation of what happens during a batch insert/mutate. Not having this CQL feature forced us to remove the Datastax Java Driver (which we liked) in favor of Astyanax because Astyanax supports this behavior.
Cassandra Alter Table, names and that the table is not defined with compact storage option. CQL3 makes one very important changes to how it presents Cassandra data: wide rows are "transposed" and unpacked into named columns. From a relational standpoint, you can think of storage engine rows as partitions, within which (object) rows are clustered. The songs data doesn't really change, since we had a static set of columns defined there: