Summarizing Records ¶ ↑Ĭounting records is easy using count: posts. Please read the Security Guide for details on security issues that you should be aware of when using Sequel. Security ¶ ↑ĭesigning apps with security in mind is a best practice. See the Dataset Filtering file for more details. # Print out the number of records puts "Item count: # create_table :items do primary_key :id String :name Float :price end items = DB # Create a dataset # Populate the table items. sqlite # memory database, requires sqlite3 DB. Installation ¶ ↑ gem install sequel A Short Example ¶ ↑ require 'sequel' DB = Sequel. If you have any comments or suggestions please post to the Google group. To check out the source code: git clone git:///jeremyevans/sequel.git Contact ¶ ↑ Only use the the bug tracker to report bugs in Sequel, not to ask for help on using Sequel. If you have questions about how to use Sequel, please ask on the sequel-talk Google Group. jeremyevans/sequel/discussions Alternate Discussion Forum (sequel-talk Google Group) jeremyevans/sequel/issues Discussion Forum (GitHub Discussions) jeremyevans/sequel Bug tracking (GitHub Issues) Sequel currently has adapters for ADO, Amalgalite, IBM_DB, JDBC, MySQL, Mysql2, ODBC, Oracle, PostgreSQL, SQLAnywhere, SQLite3, and TinyTDS. Sequel supports advanced database features such as prepared statements, bound variables, savepoints, two-phase commit, transaction isolation, primary/replica configurations, and database sharding. Sequel includes a comprehensive ORM layer for mapping records to Ruby objects and handling associated records. Sequel provides thread safety, connection pooling and a concise DSL for constructing SQL queries and table schemas. Sequel is a simple, flexible, and powerful SQL database access toolkit for Ruby. This statement disappeared from common usage as we became more set-oriented.Sequel: The Database Toolkit for Ruby ¶ ↑ This would open a file and buffer the first record (Rows and records were confused back then) in many of the early products. It existed because early SQL products were still based on filesystems. Its function was to return zero or exactly one row from a query. The original SELECT INTO in ANSI/ISO standard SQL is known as the "Singleton SELECT" and had nothing to do with copying data from one table to another. When creating a new target table, I noticed that none of the keys and indexes were created in the new table. Thank you for your informative article on SELECT INTO. If you want them present, you either use a CREATE TABLE statement followed by an INSERT INTO statement, or you use the SELECT INTO and create every index/constraint with a CREATE INDEX/CONSTRAINT statement. If you want to use INSERT INTO … SELECT, you can learn more aboutĪs I mentioned in the limitations section, indexes and constraints are not transferred from the source table.SQL Server Performance of SELECT INTO vs INSERT INTO for temporary tables Performance Improvement for SQL Server SELECT. You can read more about performance in the following tips: Using SELECT … INTO can have some performance benefits as the operation.Local vs Global SQL Server Temporary Tables. You can learn more about temporary tables in the tip.SELECT.INTO Enhancements in SQL Server 2017. SQL Server 2017 had some enhancements for the INTO clause.In this tip, Sergey introduces the construct with easy to followĮxamples and he also explains some more advanced concepts such as specifying A good introduction to the SELECT … INTO construct can be found inĬreating a table using the SQL SELECT INTO clause - Part 1 and.If you specify an ORDER BY clause, the order of the inserted rows is still.One exception is the IDENTITY constraint, but there are a couple of conditions. Like with partitioning, those properties are not transferred from the source You cannot specify indexes, constraints, computed columns or triggers.Even if the source table used in the SELECT is partitioned, There are some drawbacks when you use SELECT … INTO to create a new table. Once the stored proc is over, the data can be discarded.Įven though you can insert into a new temp table, you cannot use SELECT … For example, when you are debuggingĪ query, or in a stored procedure when you want to write intermediate results toĭisk. Using INTO and temp tables is useful when you want to dump data into a table,īut you only have use for it for a limited time. As long as there is at least one connection open that is referencing the global
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |