database-schema

问题 Please consider the following scenario. We have a 0NF table StudentTeacherTable: StudentName StudentDepartment StudentDepartmentAdd TeacherName TeacherDepartment TeacherDepartmentAdd John CS London Dave Eng, CS Oxford Mike CS London Dave Eng, CS Oxford Chris Eng Oxford Dave Eng, CS Oxford Ideally after normalization I would like to have tables like Student Table: StudentName Department TeacherName John CS Dave Mike CS Dave Chris Eng Dave Teacher Table: Name Dave TeacherDepartment Table:

问题 Please consider the following scenario. We have a 0NF table StudentTeacherTable: StudentName StudentDepartment StudentDepartmentAdd TeacherName TeacherDepartment TeacherDepartmentAdd John CS London Dave Eng, CS Oxford Mike CS London Dave Eng, CS Oxford Chris Eng Oxford Dave Eng, CS Oxford Ideally after normalization I would like to have tables like Student Table: StudentName Department TeacherName John CS Dave Mike CS Dave Chris Eng Dave Teacher Table: Name Dave TeacherDepartment Table:

问题 I am looking for information concerning the following: What are the best practices for updating the schema of my dev DB to my production DB, or even more succinctly making DB schema changes in general. The production database is the back-end for two distinct ASP.NET websites. Our schema change process is fairly robust with each "migration" actually being a .cs file containing the schema changes. We will then use ADO.NET to apply the schema changes against the db. My question is more about the

问题 I want to be able to create schedules that can be executed based on a fixed date, repeated daily, repeated on a particular day of the week, repeated on a particular month of the year, repeated on a particular date every year, and repeated at a particular time of the day. Please how do i go about building the database tables for this problem? Edit #1 Basically, i'm writing an application that allows users to schedule pre-configured greetings to be sent at various pre-configured times. I know i

问题 I am having bit of trouble with the psycopg2 Python module. I wrote a small code to extract some information from PostgreSQL table using psycopg2 module. I want to know the data type for each columns in the table: import os, psycopg2, getpass, sys, string userpass = getpass.getpass() # Connect to the database conn = psycopg2.connect("host=hostname dbname=db user=username password=%s" % (userpass)) cur = conn.cursor() cur.execute("SELECT * FROM database.table;") fieldTypes = [desc[1] for desc

问题 I'm having a bit of a trouble with the continuous queries in influxdb 0.8.8. I'm trying to create a continuous query but it seems that the where clauses are ignored. I'm aware about the restrictions mentioned here: http://influxdb.com/docs/v0.8/api/continuous_queries.html but I don't consider that this would be the case here. One row in the time series would contain data like this: {"hex":"06a0b6", "squawk":"3421", "flight":"QTR028 ", "lat":99.867630, "lon":66.447365, "validposition":1,

问题 I am not an expert so I'd really appreciate if you are real specific on your answers. I have this registration form that has a section with lots of check-boxes, and I wondering what the best way is to save this in the database. I am not sure if all values should go to a single column, or If I should create a different table only for this section of my registration form. It's also important to take into account that I will later need to pull all this data from the database and to show it in

问题 I am not an expert so I'd really appreciate if you are real specific on your answers. I have this registration form that has a section with lots of check-boxes, and I wondering what the best way is to save this in the database. I am not sure if all values should go to a single column, or If I should create a different table only for this section of my registration form. It's also important to take into account that I will later need to pull all this data from the database and to show it in

问题 I have a database with schema public and schema_A . I need to create a new schema schema_b with the same structure than schema_a . I found the function below, the problem is that it does not copy the foreign key constraints. CREATE OR REPLACE FUNCTION clone_schema(source_schema text, dest_schema text) RETURNS void AS $BODY$ DECLARE object text; buffer text; default_ text; column_ text; BEGIN EXECUTE 'CREATE SCHEMA ' || dest_schema ; -- TODO: Find a way to make this sequence's owner is the

问题 To prevent the usage of the schema attribute in the table annotation to all of my entities, I set the default schema name by the schema.xml: <?xml version="1.0" encoding="UTF-8"?> <entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd" version="2.0"> <persistence-unit-metadata> <persistence-unit-defaults> <schema>X</schema> </persistence-unit-defaults>