2. Alter table

2.1. Synopsis

 ALTER TABLE { <entries> | <find_expression> } [, ... ] ADD
   { <column_name> <data_type> }
   [, ... ]

 ALTER TABLE { <entries> | <find_expression> } [, ... ] RENAME
   { <current_column_name> TO <new_column_name> }
   [, ... ]

 ALTER TABLE { <entries> | <find_expression> } [, ... ] DROP COLUMN
   { <column_name> }
   [, ... ]

find_expression ::=
  FIND ( { <tag_expression> | NOT <tag_expression> } [ AND ... ] )

tag_expression ::=
  TAG = 'tag_name'

2.2. Description

ALTER TABLE will modify one or more tables in a QuasarDB cluster by adding, renaming or dropping columns with the specified schema. The statement is transactional.

2.3. Parameters

table_name

The name of the table to be modified. Can be alphanumeric, but is not allowed to start with a number.

find_expression

When your tables are tagged, you can use inline key/value lookups to perform your query over multiple tables. To match all tables that have the tag “stocks”, you can use FIND(tag='stocks' AND type=ts).

column_name, current_column_name, new_column_name

The name of a column to be added, renamed or dropped. Can be alphanumeric, but is not allowed to start with a number.

data_type

The data type to be associated with the column. Can be any of INT64, DOUBLE, BLOB, TIMESTAMP, STRING or SYMBOL.

2.4. Examples

Add a single column to an existing table:

ALTER TABLE example ADD my_int INT64

Add multiple columns to an existing table:

ALTER TABLE example ADD my_int INT64, my_double DOUBLE, my_blob BLOB, my_ts TIMESTAMP, my_symbol SYMBOL(my_symtable)

Rename a single column of an existing table:

ALTER TABLE example RENAME my_int TO my_new_int

Rename multiple columns of an existing table:

ALTER TABLE example RENAME my_int TO my_new_int, my_double TO my_new_double

Swap names of columns in an existing table:

ALTER TABLE example RENAME column_a TO column_b, column_b TO column_a

Drop a single column from an existing table:

ALTER TABLE example DROP COLUMN my_column

Drop multiple columns from an existing table:

ALTER TABLE example DROP COLUMN column_a, column_b, column_c