Sony FX30 has a
26.0MP APS-C (23.5 x 15.6 mm ) sized BSI-CMOS sensor and features Bionz XR processor. On the other hand, Sony A230 has a
10.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor and features Bionz processor.
Sony FX30's sensor provides 16MP more than Sony A230's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the FX30 and A230 sensor size comparison.
Sony FX30 and Sony A230 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.