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Databases & SQL vocabulary · Tables, Schemas and Database Objects

ALTER TABLE

Meaning in databases & SQL, with examples

phraseCore term

In databases & SQL, ALTER TABLE means: The SQL statement that changes the structure of an existing table, for example to add, rename or drop a column or to add a constraint.

In Turkish: tablo değiştirme komutu, ALTER TABLE

How it is used

Part of DDL. On small tables it is instant, but on large production tables some ALTER TABLE operations rewrite or lock the whole table, so teams plan them carefully, run them at quiet hours or use online schema change tools.

Example sentences

  1. The ALTER TABLE locked the orders table for ten minutes during peak hours.

  2. Write an ALTER TABLE to add a NOT NULL column with a default value.

Common collocations

  • ALTER TABLE ADD COLUMN
  • ALTER TABLE statement
  • run an ALTER TABLE
  • online schema change
  • CREATE TABLEThe SQL statement that makes a new table, defining its name, its columns with their data types and its constraints such as the primary key.
  • DDLData definition language: the SQL statements that create, change and remove database objects, such as CREATE, ALTER and DROP.
  • migrationA versioned script that changes a database schema in a controlled way, or, more broadly, a project to move data from one database or system to another.
  • columnA vertical part of a table with a name and a data type, holding one kind of information for every row, such as email or created_at.
  • lockA mark the database places on a row, page or table so that other transactions cannot change it, or sometimes read it, until the current transaction ends.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Tables, Schemas and Database Objects

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