The lookup( function searches a database for a value, then returns other information from the same record. For example, the lookup( function can look up a phone number given a customer name, or look up a price given a part number.
This function has six parameters:
database – is the database that will be searched. This database must be currently open. If this parameter is
"" then the current database will be scanned. Note: The lookup( function will search all records in the database, including records that are not currently selected. If you want to search only selected records, use the lookupselected( function.
keyfield – is the name of the field that you want to search in. For example if you want to look up all checks written to a certain vendor, this should be the field that contains vendor names. The field must be in the database specified by the first parameter. (Note: For compatibility with older versions of Panorama, you are allowed to quote this parameter but quoting is not necessary.)
keydata – is the actual data that you want to search for. For example if you want to look up all checks written to a certain vendor, this should be the actual vendor name. This parameter is often a field in the current database, but it could also be a variable, a constant, or a general expression.
datafield – is the name of the field that you want to retrieve data from. For example if you want to retrieve check numbers, this should be the name of the field that contains check numbers. This must be a field in the database specified by the first parameter.
default – is the value you want this function to return if it is unable to find the information specified by the keyfield and keydata parameters. The data type of the default value should match the data type of the datafield. If the datafield is numeric, the default should usually be zero. If the datafield is text, the default should usually be
"". Note: This parameter is optional. If it is omitted, the lookup( function will return an error if the search fails.
level – is the minimum summary level to be searched. Usually this parameter is zero so that the entire database will be searched. If the level is set to 1 through 7, only summary records will be searched. Note: This parameter is optional. If it is omitted, all records will be searched.
This function searches a database looking for records where the keyField matches the specified keyValue. When it finds a match, it stops searching and returns the contents of the requested dataField from that record.
Note: To learn more about the theory and technical details about working with links between databases, see Linking with Another Database. The lookup( function can also be constructed automatically for you with the Relational Workshop wizard.
To illustrate this function, assume that you have a Price List database that contains fields named Product and Price, and that your current database contains a field named Item that contains a product name. This formula will look up the price:
If there is no product that matches the name in Item, the formula above will result in an error. Adding a default value eliminates the possibility of this error:
If a default value is supplied, it should have the same data type as the DataField parameter. In this case, the Price field is numeric, so the default value is numeric also.
This example assumes you have a Vendors database with Company and PaymentCategory field. (It also assumes the current database has a Name field that contains company names.) If the company name is not found in the Vendors database, this formula returns None as the category:
Of course you could also return nothing as the default:
In a procedure, you could use multiple lookup( functions in a row to transfer multiple fields.
Address=lookup("Customers",Company,Company,Address,"") City=lookup("Customers",Company,Company,City,"") State=lookup("Customers",Company,Company,State,"") Zip=lookup("Customers",Company,Company,Zip,"")
Since each lookup( function can only transfer one value, four lookups are required. However, Panorama doesn’t actually search the Customers file four times. When a procedure performs multiple lookups with the same target database, key field, and key value Panorama realizes that it doesn’t have to re-search the database – it already knows where the data is, and it just goes and gets it. (If your database is set up for it, you can use the speedcopy statement to move this data even faster.)
|10.0||Updated||Carried over from Panorama 6.0, but now the default and level parameters are optional. Also, you now are allowed to use "" to specify the current database.|