ALTER TABLE¶

Use the ALTER TABLE statement to add and drop columns in row tables using SnappyData API or SQL.

Note

ALTER TABLE is not supported on column, temporary and external tables.
For row tables, only adding and dropping a column is supported using Snappy APIs or SQL.

Syntax¶

SQL

ALTER TABLE table-name
{
  ADD COLUMN column-definition |
  DROP COLUMN column-name
}

API:

snc.alterTable(tableName, isAddColumn, column)

Example¶

SQL:

-- create a table
CREATE TABLE trade.customers (
    cid int not null,
    cust_name varchar(100),
    addr varchar(100),
    tid int);

-- drop a non-primary key column if the column is not used for table partitioning, and the column has no dependents
ALTER TABLE trade.customers DROP COLUMN addr;

-- add the column back with a default value
ALTER TABLE trade.customers ADD COLUMN addr varchar(100);

API:

//create a table in Snappy store
    snc.createTable("orders", "row", ordersDF.schema, Map.empty[String, String])

//alter table add/drop specified column, only supported for row tables.

// for adding a column isAddColumn should be true
    snc.alterTable("orders", true, StructField("FirstName", StringType, true))

// for dropping a column isAddColumn should be false
    snc.alterTable("orders", false, StructField("FirstName", StringType, true))