Sql Generate Create Table Script With Indexes And Primary Key
I found this answer on mssqltips and this is the link to the article I found there. I am also posting the TSQL for possible link-rot in future. T-SQL Script to Drop All SQL Server Indexes. DECLARE @SchemaName VARCHAR(256)DECLARE @TableName VARCHAR(256) DECLARE @IndexName VARCHAR(256) DECLARE @TSQLDropIndex VARCHAR(MAX) DECLARE CursorIndexes CURSOR FOR. SQL FOREIGN KEY Constraint. A FOREIGN KEY is a key used to link two tables together. A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table. The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table. I want to generate create table script of already created table in my live database. I know we can generate scripts using right click on table and click on 'script table as' menu and script will be generated. Because my live db UI is running very slow. I want to do same process using SQL query. Is there any way?? AUTO INCREMENT Field. Auto-increment allows a unique number to be generated automatically when a new record is inserted into a table. Often this is the primary key field that we would like to be created automatically every time a new record is inserted. Apr 18, 2008 SQL SERVER – Generate Foreign Key Scripts For Database. April 18, 2008. Many times there are situations where one need to drop all the foreign key and add them back. This SQL Script can be used for the same purpose. PRIMARY Table 2 – CREATE TABLE. Mar 24, 2010 So, if the table is already created, the primary key will not be created if you use the script that was generated by the SSMS Generate Scripts Wizard. The steps that you need to follow are for generating the primary key constraints or clustered indexes for user defined tables: 1.
Create and delete tables
Tables are the primary building blocks of a relational database. A table contains rows (or records) of data, and each row is organized into a finite number of columns (or fields). To build a new table in Access by using Access SQL, you must name the table, name the fields, and define the type of data that the fields will contain. Use the CREATE TABLE statement to define the table in SQL. Suppose that you are building an invoicing database. The first step is to build the initial customers table.
Be aware of the following issues when creating and deleting tables:
If a field name includes a space or some other nonalphanumeric character, you must enclose that field name within square brackets ([ ]).
If you do not declare a length for text fields, they will default to 255 characters. For consistency and code readability, you should always define your field lengths.
You can declare a field to be NOT NULL, which means that null values cannot be inserted into that particular field; a value is always required. A null value should not be confused with an empty string or a value of 0; it is simply the database representation of an unknown value.
To remove a table from the database, use the DROP TABLE statement.
Create and delete indexes
An index is an external data structure used to sort or arrange pointers to data in a table. When you apply an index to a table, you are specifying a certain arrangement of the data so that it can be accessed more quickly. However, if you apply too many indexes to a table, you may slow down the performance because there is extra overhead involved in maintaining the index, and because an index can cause locking issues when used in a multiuser environment. Used in the correct context, an index can greatly improve the performance of an application.
To build an index on a table, you must name the index, name the table to build the index on, name the field or fields within the table to use, and name the options you want to use. You use the CREATE INDEX statement to build the index. For example, you could build an index on the customers table in the invoicing database mentioned earlier by using the following code:
Indexed fields can be sorted in one of two ways: ascending (ASC) or descending (DESC). The default order is ascending, and it does not have to be declared. If you use ascending order, the data will be sorted from 1 to 100. If you specify descending order, the data will be sorted from 100 to 1. You should declare the sort order with each field in the index.
There are four main options that you can use with an index: PRIMARY, DISALLOW NULL, IGNORE NULL, and UNIQUE. The PRIMARY option designates the index as the primary key for the table. You can have only one primary key index per table, although the primary key index can be declared with more than one field. Use the WITH keyword to declare the index options.
To create a primary key index on more than one field, include all of the field names in the field list.
The DISALLOW NULL option prevents insertion of null data in the field. (This is similar to the NOT NULL declaration used in the CREATE TABLE statement.)
The IGNORE NULL option causes null data in the table to be ignored for the index. That means that any record that has a null value in the declared field will not be used (or counted) in the index.
In addition to the PRIMARY, DISALLOW NULL, and IGNORE NULL options, you can also declare the index as UNIQUE, which means that only unique, non-repeating values can be inserted in the indexed field.
To remove an index from a table, use the DROP INDEX statement.
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Similar to MySQL, PostgreSQL, Oracle, and many other relational databases, SQL Server is best utilized when assigning unique primary keys to most database tables.
The advantages to using numeric, auto incremented primary keys are numerous, but the most impactful benefits are faster speed when performing queries and data-independence when searching through thousands of records which might contain frequently altered data elsewhere in the table. With a consistent and unique numeric identifier, applications can take advantage of these faster and more reliable queries.
Basic Table Creation
Once connected to your SQL Server, you’d normally start by CREATING a new table that contains the the field you wish to use as your incremented primary key. For our example, we’ll stick with the tried and true id field:
The problem here is, we have no way of controlling our id field. When a new record is inserted, we not only must manually enter a value for id, but we have to perform a query ahead of time to attempt to verify that id value doesn’t already exist (a near-impossibility when dealing with many simultaneous connections).
Using Identity and Primary Key Constraints
/ecdsa-key-pair-generation-java.html. The solution turns out to be using two constraint options provided by SQL Server.
The first is PRIMARY KEY, which as the name suggests, forces the specified column to behave as a completely unique index for the table, allowing for rapid searching and queries.
While SQL Server only allows one PRIMARY KEY constraint assigned to a single table, that PRIMARY KEY can be defined for more than one column. In a multi-column scenario, individual columns can contain duplicate, non-unique values, but the PRIMARY KEY constraint ensures that every combination of constrained values will in fact be unique relative to every other combination.
The second piece of the puzzle is the IDENTITY constraint, which informs SQL Server to auto increment the numeric value within the specified column anytime a new record is INSERTED. While IDENTITYcan accept two arguments of the numeric seed where the values will begin from as well as the increment, these values are typically not specified with the IDENTITY constraint and instead are left as defaults (both default to 1).
Sql Generate Create Table Script With Indexes And Primary Key Examples
With this new knowledge at our fingertips, we can rewrite our previous CREATE TABLE statement by adding our two new constraints.
Create Table On Primary Sql
That’s all there is to it. Now the id column of our books table will be automatically incremented upon every INSERT and the id field is guaranteed to be a unique value as well.