I am estimating two regressions. The first is a regression with only dummy variables (i.e. $y = B_0 + B_1D_1 + B_2D_2$), and the second is with two independent variables (i.e. $y = B_0 + B_1X_1 + B_2X_2 + B_3D_1 + B_4D_2$).
The $D_1$ and $D_2$ are dummy variables, whereas the $X_1$ and $X_2$ are continuous. Would there be a difference in the meaning/interpretation of the B1 in the first regression and the B3 in the second regression (both the coefficient of the first dummy variable)?