sql server add primary key to existing table with data code example
Example 1: add primary key to existing table sql
alter table Persion add primary key (persionId,Pname,PMID)
Example 2: primary key in sql
PRIMARY KEY
-- unique identifier for the entire row of record in a table
-- can not be null and must be unique
Example 3: sql primary key
-- NOTE: this is for SQL-Oracle specifically
-- example:
SELECT cols.table_name, cols.column_name, cols.position, cons.status, cons.owner
FROM all_constraints cons, all_cons_columns cols
WHERE cols.table_name = 'CUSTOMERS'
AND cons.constraint_type = 'P'
AND cons.constraint_name = cols.constraint_name
AND cons.owner = cols.owner;
-- syntax:
SELECT cols.table_name, cols.column_name, cols.position, cons.status, cons.owner
FROM all_constraints cons, all_cons_columns cols
WHERE cols.table_name = '<table-name>' -- Replace <table-name> with your table-name
AND cons.constraint_type = 'P'
AND cons.constraint_name = cols.constraint_name
AND cons.owner = cols.owner;
Example 4: sql server add primary key to existing table with data
ALTER TABLE Production.TransactionHistoryArchive
ADD CONSTRAINT PK_TransactionHistoryArchive_TransactionID PRIMARY KEY CLUSTERED (TransactionID);