The reason is in the subscriber, rows are updated/deleted one-by-one using primary key. For example: If you delete 100 rows in the publisher using a single DELETE statement, in the subscriber 100 DELETE statements would be executed.

Is primary key required for replication?

There are a number of issues to consider regarding constraints on published tables: Transactional replication requires a primary key constraint on each published table. Merge replication does not require a primary key, but if one is present, it must be replicated. Snapshot replication does not require a primary key.

Why is a primary key necessary?

Without the primary key and closely related foreign key concepts, relational databases would not work. In fact, since a table can easily contain thousands of records (including duplicates), a primary key is necessary to ensure that a table record can always be uniquely identified.

What is a primary key Why is it important when is it necessary for the primary key to include multiple fields?

A primary key is either an existing table column or a column that is specifically generated by the database according to a defined sequence. The primary key concept is critical to an efficient relational database. Without the primary key and closely related foreign key concepts, relational databases would not work.

Is primary key always necessary?

Every table can have (but does not have to have) a primary key. The column or columns defined as the primary key ensure uniqueness in the table; no two rows can have the same key. The primary key of one table may also help to identify records in other tables, and be part of the second table’s primary key.

What is a primary key Why is it necessary to have a primary key in a table Class 8?

Answer: Primary key is a field that uniquely identifies each record in a table. For example, in a school database, the Roll Number of each student uniquely identifies each student. A Primary key does not allow Null Values and must always have a unique value.

Does every entity need a primary key?

The primary key is an attribute or a set of attributes that uniquely identify a specific instance of an entity. Every entity in the data model must have a primary key whose values uniquely identify instances of the entity.

What is a primary key explain with the help of an example?

A primary key is a column — or a group of columns — in a table that uniquely identifies the rows in that table. For example, in the table below, CustomerNo, which displays the ID number assigned to different customers, is the primary key.

How does a primary key help in Organising a database?

A primary key is used to ensure data in the specific column is unique. You can only set constraints with primary keys, by setting a foreign key to another column which creates a relationship with the column that has the primary key set. A prime use of a primary key is in the case of a users table.

What is primary key in relational database?

A primary key is a column or a set of columns in a table whose values uniquely identify a row in the table. A relational database is designed to enforce the uniqueness of primary keys by allowing only one row with a given primary key value in a table.