Adding a column to a table is common task for DBAs. You can add a column to a table which is a nullable column or which has default values. But are these two operations are similar internally and which method is optimal? Let us start this with an example. I created a database and a...
Set up this KiSSFLOW SQL Server integration to keep up with the activity no matter how fast it happens. It will trigger with every workflow step change on your KiSSFLOW processes, automatically adding a new row to your SQL Server table for each one from then on....
public static DataTable GetDataTable(string tblName, bool identity, int seed, int step, Dictionary<string, string> cellNameType, List<Dictionary<string, string>> valueList) { //这个数据表的名字要和数据库中一致 DataTable dt = new DataTable(tblName); DataColumn dc = null; foreach (var ite...
Most of you must have come across the pain of adding a not null column with a default value to an existing big table. It takes minutes to add columns. I recently found out that this problem has been resolved in SQL Server 2012. Let’s look into some ways to resolve this in versions ...
在SQL Server 中插入一条数据使用Insert语句,但是如果想要批量插入一堆数据的话,循环使用Insert不仅效率低,而且会导致SQL一系统性能问题。下面介绍SQL Server支持的两种批量数据插入方法:Bulk和表值参数(Table-Valued Parameters)。 运行下面的脚本,建立测试数据库和表值参数。
alter table Staging switch to Fact partition @p; go -- Retrieve the rows in the partitioned table, showing the partition of each row. select $partition.pf(date_key) as partition_number, * from Fact; go Existing techniques and guidelines for using SQL Ser...
在结果就能看到数据库所有表的结构，这个时候只要全选，然后右击出来属性框，选择将结果另存为，这个时候...
ALTER TABLE table_name ADD column_name tada_type NOT NULL CONSTRAINT constraint_name DEFAULT default_value; If you set the new column nullable, that column value for all existing rows will be NULL instead of the default value. In that case, you can addWITH VALUESto the statem...
A standard user-defined table can have up to 1,024 columns. The number of rows in the table is limited only by the storage capacity of the server. You can assign properties to the table and to each column in the table to control the data that is allowed and other properties. For ...
BEGIN TRANSACTION; SELECT col1 FROM TestTable WITH (TABLOCKX, HOLDLOCK); 数据库引擎中基于行版本控制的隔离级别 从SQL Server 2005 (9.x) 开始,数据库引擎提供现有事务隔离级别 (READ COMMITTED) 的实现,该实现使用行版本控制提供语句级快照。 数据库引擎还提供一个事务隔离级别 (SNAPSHOT),该级别也使用行...