An ID column holds a unique value for each row in a table. This is commonly used to provide relationships between tables.
- An ID column is a column that holds…a unique value for each row in a table.…Typically ID columns are automatically populated.…The method for creating an ID column is not standardized.…How you create the ID column is different…for every database system.…This is how it works in SQL light,…the database system we're using here,…and I'm showing you this just so…you have an idea of how it works.…But know that the specific syntax…will be different on different systems.…
Here we're using the in memory database…and I've already pasted some SQL code in here.…The first statement is a create table statement…which will create a table with three columns,…the ID column, and two columns named A and B,…integer and text respectively.…For SQL light you use and integer type with the primary key…constraint and the system will automatically generate…a unique sequential number and will enforce…a unique value constraint.…The name of the column is not important.…It can be anything, I tend to use ID just for consistency.…
Then we'll add some rows to the table…
- Understanding SQL terminology and syntax
- Creating new tables
- Inserting and updating data
- Writing basic SQL queries
- Sorting and filtering
- Accessing related tables with JOIN
- Working with strings
- Understanding numeric types
- Using aggregate functions and transactions
- Automating data with triggers
- Creating views
- Defining functions in PHP
Skill Level Beginner
2. SQL Overview
3. Fundamental Concepts
7. Dates and Times
Dates and times1m 52s
11. Views and Subselects
12. Defined Functions
13. A Simple CRUD Application
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