Customize import options when importing data from a database table. Control the import options by creating an SQLImportOptions object. Then, customize import options for different database columns. Import data using the sqlread function.
This example uses the patients.xls file, which contains the columns Gender, Location, SelfAssessedHealthStatus, and Smoker. The example also uses a Microsoft® SQL Server® Version 11.00.2100 database and the Microsoft SQL Server Driver 11.00.5058.
Create a database connection to a Microsoft SQL Server database with Windows® authentication. Specify a blank user name and password.
Load patient information into the MATLAB® workspace.
Create the patients database table using the patient information.
Create an SQLImportOptions object using the patients database table and the databaseImportOptions function.
opts =
SQLImportOptions with properties:
ExcludeDuplicates: false
VariableNamingRule: 'modify'
VariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
VariableTypes: {'char', 'char', 'double' ... and 7 more}
SelectedVariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
FillValues: {'', '', NaN ... and 7 more }
VariableOptions: Show all 10 VariableOptions
Display the current import options for the variables selected in the SelectedVariableNames property of the SQLImportOptions object.
varOpts =
1x10 SQLVariableImportOptions array with properties:
Variable Options:
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10)
Name: 'LastName' | 'Gender' | 'Age' | 'Location' | 'Height' | 'Weight' | 'Smoker' | 'Systolic' | 'Diastolic' | 'SelfAssessedHealthStatus'
Type: 'char' | 'char' | 'double' | 'char' | 'double' | 'double' | 'double' | 'double' | 'double' | 'char'
MissingRule: 'fill' | 'fill' | 'fill' | 'fill' | 'fill' | 'fill' | 'fill' | 'fill' | 'fill' | 'fill'
FillValue: '' | '' | NaN | '' | NaN | NaN | NaN | NaN | NaN | ''
To access sub-properties of each variable, use getoptions
Change the data types for the Gender, Location, SelfAssessedHealthStatus, and Smoker variables using the setoptions function. Because the Gender, Location, and SelfAssessedHealthStatus variables indicate a finite set of repeating values, change their data type to categorical. Because the Smoker variable stores the values 0 and 1, change its data type to logical. Then, display the updated import options.
varOpts =
1x4 SQLVariableImportOptions array with properties:
Variable Options:
(1) | (2) | (3) | (4)
Name: 'Gender' | 'Location' | 'Smoker' | 'SelfAssessedHealthStatus'
Type: 'categorical' | 'categorical' | 'logical' | 'categorical'
MissingRule: 'fill' | 'fill' | 'fill' | 'fill'
FillValue: <undefined> | <undefined> | 0 | <undefined>
To access sub-properties of each variable, use getoptions
Import the patients database table using the sqlread function, and display the last eight rows of the table.
ans=8×10 table
LastName Gender Age Location Height Weight Smoker Systolic Diastolic SelfAssessedHealthStatus
_____________ ______ ___ _________________________ ______ ______ ______ ________ _________ ________________________
{'Foster' } Female 30 St. Mary's Medical Center 70 124 false 130 91 Fair
{'Gonzales' } Male 48 County General Hospital 71 174 false 123 79 Good
{'Bryant' } Female 48 County General Hospital 66 134 false 129 73 Excellent
{'Alexander'} Male 25 County General Hospital 69 171 true 128 99 Good
{'Russell' } Male 44 VA Hospital 69 188 true 124 92 Good
{'Griffin' } Male 49 County General Hospital 70 186 false 119 74 Fair
{'Diaz' } Male 45 County General Hospital 68 172 true 136 93 Good
{'Hayes' } Male 48 County General Hospital 66 177 false 114 86 Fair
Display a summary of the imported data. The sqlread function applies the import options to the variables in the imported data.
Variables:
LastName: 100×1 cell array of character vectors
Gender: 100×1 categorical
Values:
Female 53
Male 47
Age: 100×1 double
Values:
Min 25
Median 39
Max 50
Location: 100×1 categorical
Values:
County General Hospital 39
St. Mary s Medical Center 24
VA Hospital 37
Height: 100×1 double
Values:
Min 60
Median 67
Max 72
Weight: 100×1 double
Values:
Min 111
Median 142.5
Max 202
Smoker: 100×1 logical
Values:
True 34
False 66
Systolic: 100×1 double
Values:
Min 109
Median 122
Max 138
Diastolic: 100×1 double
Values:
Min 68
Median 81.5
Max 99
SelfAssessedHealthStatus: 100×1 categorical
Values:
Excellent 34
Fair 15
Good 40
Poor 11
Delete the patients database table using the execute function.
Close the database connection.
