indexing

问题 I'm querying a very large table (over 3M records) in MySQL that has a category_id, subcategory_id and zipcode. The zip may or may not be 10 characters in the db. The purpose is to get all the cat/subcat items w/in a certain radius of the specified zip. I have a function that returns a list of 5-digit zips for one specified. This list is then fed to my query like so... SELECT whatever FROM tblName WHERE cat_id = 1 AND subcat_id = 5 AND LEFT(zip,5) IN (11111,22222,33333,44444,55555) I have a

问题 I'm querying a very large table (over 3M records) in MySQL that has a category_id, subcategory_id and zipcode. The zip may or may not be 10 characters in the db. The purpose is to get all the cat/subcat items w/in a certain radius of the specified zip. I have a function that returns a list of 5-digit zips for one specified. This list is then fed to my query like so... SELECT whatever FROM tblName WHERE cat_id = 1 AND subcat_id = 5 AND LEFT(zip,5) IN (11111,22222,33333,44444,55555) I have a

问题 I have some adverts on my site. This adverts are images and not closed in <a> tag. I store adverts URLs in JS array advertisement . When user clicks on advert the next JS code executed: $(".jLinkBlank").click(function() { var adverId = parseInt($(this).attr('id').substring(5)); var url = advertisement[adverId]; window.open(url, '_blank'); }); But as I see Google indexing such URLs in any case. How can I prevent such URLs from Google indexation? Solutions like robots.txt or <META NAME="ROBOTS"

问题 Ok here is a non clustered index features Now as you can see Id is the Identity column which is primary key and clustered. I can either include it into the index columns and mark index as unique or not include it to the index itself and add it as included columns. Which one should be selected and why ? thank you 回答1: The clustered key is automatically included in the nonclustered index, whether you include it explicitly or not. In other words - don't include it, unless you need to use a

问题 I have some data that I would like to aggregate, but I'm getting the index out of bounds error, and I can't seem to figure out why. Here's my code: if period == "hour": n=3 tvec_a=np.zeros([24,6]) tvec_a[:,3]=np.arange(0,24) data_a=np.zeros([24,4]) elif period == "day": n=2 tvec_a=np.zeros([31,6]) tvec_a[:,2]=np.arange(1,32) data_a=np.zeros([31,4]) elif period == "month": n=1 tvec_a=np.zeros([12,6]) tvec_a[:,1]=np.arange(1,13) data_a=np.zeros([12,4]) elif period == "hour of the day": tvec_a

问题 I have some data that I would like to aggregate, but I'm getting the index out of bounds error, and I can't seem to figure out why. Here's my code: if period == "hour": n=3 tvec_a=np.zeros([24,6]) tvec_a[:,3]=np.arange(0,24) data_a=np.zeros([24,4]) elif period == "day": n=2 tvec_a=np.zeros([31,6]) tvec_a[:,2]=np.arange(1,32) data_a=np.zeros([31,4]) elif period == "month": n=1 tvec_a=np.zeros([12,6]) tvec_a[:,1]=np.arange(1,13) data_a=np.zeros([12,4]) elif period == "hour of the day": tvec_a

问题 In my app I have a concept of "seasons" which change discretely over time. All the entities are related to some season. All entities have season based indices as well as some indices on other fields. When season change occurs, postgresql decides to use filtered scan plan based on season index rather than more specific field indices. At the beginning of the season the planning cost of such decision is very little, so it's ok, but the problem is - season change brings MANY users to come at the

问题 Maybe a silly question, but is it safe to use a function based indexes. I mean, when the column changes is the index changed right away? 回答1: Assuming they are setup correctly, Yes. OVERVIEW: Oracle creates a hidden column on the table with the function based index which is updated each time the columns on which the function based index are changed; assuming the values are deterministic (See oracle link for more info). You can see these hidden columns by querying the system object all_tab

问题 I frequently search for a token, perhaps a function name, throughout my codebase. My traditional method would be to grep for the term itself. However, the codebase is so large that I can't do this efficiently (it takes minutes). Is there a way to do this efficiently? ack (which ignores irrelevent files such as revision control files) is still too slow. ctags only finds declarations, which isn't what I need. I thought something like strigi might work, but I haven't tried it. I'm on linux,

问题 Is there a way in JavaScript to select a element of a multidimential array. Where the depth/rank/dimensionality is variable and the keys are given by a array of indices. Such that i don't have handle every possible dimentional depth separately. concretely speaking i want do get rid of switch cases like here: /** * set tensor value by index * @type {array} indices [ index1, index2, index3 ] -> length == rank. * @type {string} value. */ tensor.prototype.setValueByIndex = function( indices,