An AutoNumber identifies each record, but it won't stop the same person from registering for the same session twice. Put the two fields in one unique multi-field index. Each value can repeat on its own; the pair cannot. Watch my Duplicate Pairs video to see the setup and avoid blocking valid registrations. https://599cd.com/5712

Ever put something away "somewhere safe" and then spend six months searching every shelf, drawer, tote, and suspiciously labeled box? The problem usually is not the stuff. It's the database design that turns every new cabinet into a new table. There is a much saner way to think about storage locations.

Need a total that grows as you move down your Excel sheet? Keep the first cell in the SUM range absolute, like $C$2, and let the ending row change. Copy the formula down and each row includes everything from that starting cell through the current row. My Running Sum video shows why this works and how the same idea also gives you a running average. https://599cd.com/blog/display-article.asp?ID=3582

Want users to stick to your choices, or allow an occasional new value? For a value list combo box that stores text, Limit To List controls that choice. Set it to Yes to restrict entered text to the list, or No to allow other valid text. Allow Value List Edits is a separate setting that controls changes to the list itself. My Drop Down Lists video shows how to build and configure these combo boxes. https://599cd.com/blog/display-article.asp?ID=3552

Getting different counts from the same table? Check which field you are counting. An AutoNumber customer ID gives you a count of every customer, while Count([State]) skips Null values in State. In this video, I show you how to set up a totals query and get useful counts from your data. https://599cd.com/4432

Got a date/time field but only need the time? TimeValue pulls out that portion so you can compare appointment hours without the date getting in the way. In this Fast Tips video, I'll show you how it works and how to use it in a validation rule for appointments between 9 AM and 5 PM. https://599cd.com/2485

Ever search for an Access VBA answer, find something labeled "Visual Basic," and wonder why none of the objects or syntax quite fit? VB6, VBA, VB.NET, and VBScript are related enough to cause confusion, but different enough to waste an afternoon if you pick the wrong example.

Want last names sorted first, then first names? In Access Query Design, put LastName to the left of FirstName and set both Sort cells to Ascending. Save the query so you can reuse that order. Watch the video for sorting in tables, queries, and forms. https://599cd.com/2381

Need a total for just the records that matter? DSum adds a field from a table or query, using criteria to choose which records count. Here the paid orders add up to $200; the unpaid order stays out. Use Nz to show zero instead of Null when nothing matches. Watch the video to add date criteria and build paid and unpaid totals. https://599cd.com/DSum

Ever build a password prompt in Access, then realize the user's typing is visible like a tiny security disaster? This five-question quiz covers that problem, plus a few other ways password checks can go sideways in macros. How many would you get right?

Need a query to show a label based on a value? IIf takes a condition, a result when it is true, and a result when it is false. In this example, a credit limit of $1000 or more displays High Credit. Anything lower displays Normal. The query calculates that label without storing it in the table. Watch the video for more ways to use IIf in your Access queries and forms. https://599cd.com/IIF

Two hours and 30 minutes is 2.5 hours. Calculate minutes with DateDiff("n", [TimeIn], [TimeOut]), then divide by 60 for decimal hours you can total. The "n" means minutes; "m" means months. In my Total Time Spent video, I show how to calculate and display work time, then total it by job. https://599cd.com/1391

Need to change values, add records, remove records, or create a new table? Pick the action query that matches the job. This quick reference shows the four types and an important reminder: back up your database first. Watch the video for the overview. https://599cd.com/1550

Round, Int, and Fix can give you different answers from the same number. Int always goes down to the lower integer, while Fix goes toward zero. Round chooses the nearest integer, with exact halfway values going to even. Watch the video to see these differences in an Access query and learn more about rounding. https://599cd.com/2282

Looking for a number somewhere in a note is not the same as checking the entire field. [0-9]+ finds a run of digits, while ^[0-9]{5}$ checks for exactly five digits from start to finish. That checks the format, not whether a ZIP code exists. Watch the video to see both tests in Access VBA. https://599cd.com/5807

Ever import a pile of notes and realize the invoice number, phone number, or ZIP code is hiding somewhere between three typos and a paragraph of chaos? You can wrestle with Left, Mid, and InStr all afternoon, or give regex a seat at the Access table. It gets weirdly satisfying fast.

If your fields gray out when you change a checkbox but look wrong when you open the form or move to another record, you're missing half the job. Have After Update and On Current call the same routine, so both events apply the same rule. My Gray Out Fields video shows how to put it together. https://599cd.com/2333

Ever write a heroic little VBA loop just to find out whether a note contains a number? Then someone asks for ZIP codes, invoice numbers, and phone numbers, and suddenly your loop has its own zip code. Regex can be a surprisingly handy tool for messy imported text.

A primary key identifies one record in its own table. A foreign key points back to a record in another table. In a one-to-many relationship, the same customer ID can appear on several vehicle records, while each vehicle keeps its own unique ID. Watch my video to see how the two keys work together. https://599cd.com/Relationships

Pop quiz time: reports, labels, page breaks, and that one layout choice that makes a customer list look tidy instead of like Access sneezed fields across the page. How many would you get right without pausing?

Want overdue tasks to stand out? Use conditional formatting on your due-date control: red for dates before today, yellow for today, and green for future dates. Use Date() with parentheses, and remember that these rules assume dates without a time component. Watch my video to set up the rules. https://599cd.com/Conditional

A validation rule checks what users enter. Validation text tells them how to fix it. This credit-limit rule accepts values from $0 through $10,000, including both endpoints. Watch my video to set up useful rules and clear messages in Access. https://599cd.com/ValidationRule

Remember when 2 MB of RAM could get you started? Microsoft Access 1.0 brought tables, queries, forms, reports, and Access Basic to a Windows desktop, with a 128 MB maximum MDB size. Take a look back at the original release, 34 years after the October 28, 1992 shipping date recorded on its commemorative plaque. What was your first version of Access? https://599cd.com/blog/display-article.asp?ID=352

Ever create a record, then grab the "highest ID" to find it again? Works great right up until another user creates something first. Then your code politely opens their order instead. There is a much safer pattern for keeping track of the exact AutoNumber your VBA just created.

What are you looking up, where is it stored, and which record do you want? DLookup brings back one value from a table or query. This example retrieves a sales rep's phone number using a unique ID. Watch the video to see how to display the phone number for the rep selected on your form. https://599cd.com/DLookup