Create Named CHECK Constraint It's a good practice to createnamed constraintsso that it is easier to alter and drop constraints. Here's an example to create a namedCHECKconstraint: -- create a named constraint
Create UNIQUE Constraint We can implement theUNIQUEconstraint at the time of table creation. For example, -- create a table with unique constraintCREATETABLEColleges ( college_idINTNOTNULLUNIQUE, college_codeVARCHAR(20)UNIQUE, college_nameVARCHAR(50) );-- insert values to Colleges tableINSERTINTOC...
Explore all SQL constraints with examples and real-world use cases. Learn PRIMARY KEY, FOREIGN KEY, UNIQUE, CHECK, and more.
These are the few constraints while working with SQL subtract dates. If the date argument is incremented to a value outside the range of its data type, then DATEADD returns an error. In the following example, the number value added to the date value exceeds the range of the date data typ...
Integrity Constraints are used to apply business rules for the database tables. The constraints available in SQL are Foreign Key, Not Null, Unique, Check.Constraints can be defined in two ways 1) The constraints can be specified immediately after the column definition. This is called column-...
TABLE_CONSTRAINTS WHERE TABLE_NAME='ConstraintDemo3' With the below result in our example: The ALTER TABLE…DROP CONSTRAINT T-SQL statement can be used easily to drop the previously defined PRIMARY KEY using the name derived from the previous result: 1 2 3 4 ALTER TABLE ConstraintDemo3 ...
Taking the example of SQL create a statement with DEFAULT constraints, create a table with name bill which contains columns bill no as PRIMARY KEY, patient_if as foreign key, room_chargers and room_charges both column value must be greater than 0, and no_of_days having constrained as NOT...
Temporary tables Genuine tables with indexes and constraints, accessible during a session. Multi-use Handling large datasets or when results need multiple references. Subqueries Inline queries without naming, compatible with WHERE clause using IN/EXISTS. Single-use Using IN/EXISTS in a WHERE clause or...
Here's the definition of a query with aWHEREclause again, go ahead and try and write some queries with the operators above to limit the results to the information we need in the tasks below. Select query with constraints SELECTcolumn, another_column, …FROMmytableWHEREconditionAND/ORanother_...
Learn more about Identity –INSERT INTO SQL Server table with IDENTITY column Learn about Default Constraints –Working with DEFAULT constraints in SQL Server Get more onSQL SELECT INTO Examples Read aboutSQL JOIN Types with Examples Read:Getting started with Stored Procedures in SQL Server ...