Learn how to use NOT NULL constraints to enforce that values for specific columns in your table must be specified when inserted.
- [Instructor] Another type of constraint…we can create on our database tables is the not now…constraint.…Not now enforces that values have to be inserted…into a specific column in the table.…So for example, note that if I try to insert…a new record into our demo table 2,…specifying only column one,…and let's provide a value of four,…so essentially telling Oracle insert a new row,…but only specify a value for column one,…let's try to insert data into the table…and see that I was successful.…
Selecting data from this table will show me…that for my newly inserted row,…because I haven't specified a value for column two,…it is listed as null,…null meaning that no value exists for this column…for this row.…However, note what will happen if I'll drop this table…and recreate it, specifying that column two…has a not now constraint on it.…So I'll type drop table demo table 2,…and recreate my table, but this time specifying…not now for column two.…
Let's execute our create table command…and try to insert the same row.…Note that this time, I got an error.…
Note: This training course is appropriate for beginning database developers with no prior experience with SQL or Oracle.
- Using Oracle SQL*Developer, the free development environment
- Selecting data from tables
- Filtering data
- Using functions to manipulate data
- Joining data from tables
- Creating tables
- Updating values
- Truncating data
- Grouping and ordering result sets
- Working with primary keys
- Checking constraints
Skill Level Beginner
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1. Introduction to SQL
2. Preparing the Course Environment
Downloading the course VM2m 16s
3. Using Oracle SQL Developer
4. Basic SELECT Queries
5. String, Number, and Date Functions
6. Joining Table Data
7. Manipulating Data
8. Grouping Data
9. Advanced Topics
Next steps1m 33s
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