Database – What is a Composite Primary Key?

Database Table What is a Composite Primary Key? A Composite Primary key is Primary key What a primary key, which is defined by having multiple fields (columns) in it.  Like a Primary Key what a composite Primary Key is depends on the database.  Essentially a Composite Primary Key: Is a combination of Fields (columns) which … Continue reading Database – What is a Composite Primary Key?

Database – What is a Primary Key?

Database Table What is a primary Key? What a primary key is depends, somewhat, on the database.  However, in its simplest form a primary key: Is a field (Column) or combination of Fields (columns) which uniquely identifies every row.Is an index in database systems which use indexes for optimizationIs a type of table constraintIs applied … Continue reading Database – What is a Primary Key?

Database – What is DDL?

SQL (Structured Query Language) What is DDL (Data Definition Language)? DDL (Data Definition Language), are the statements used to manage tables, schemas, domains, indexes, views, and privileges.  The the major actions performed by DDL commands are: create, alter, drop, grant, and revoke. Related References What is DCL?What is DML?Database Table Field Ordering Effective PracticesStructured Query Language … Continue reading Database – What is DDL?

Data Modeling – Fact Table Effective Practices

Database Table Here are a few guidelines for modeling and designing fact tables. Fact Table Effective Practices The table naming convention should identify it as a fact table. For example: Suffix Pattern: <<TableName>>_Fact <<TableName>>_F Prefix Pattern: FACT_<TableName>> F_<TableName>> Must contain a temporal dimension surrogate key (e.g. date dimension) Measures should be nullable – this has an … Continue reading Data Modeling – Fact Table Effective Practices

Database – What is DML?

What is DML (Data Manipulation Language)? As the name indicates, Data manipulation for working with information inside a database structure.  There are four main DML commands: Select - reading data rows Insert - adding data rows update - changing values within data rows Delete - removing data row Related References What is DCL?  

Data Modeling – Dimension Table Effective Practices

Database Table I've had these notes laying around for a while, so, I thought I consolidate them here.   So, here are few guidelines to ensure the quality of your dimension table structures. Dimension Table Effective Practices The table naming convention should identify it as a dimension table. For example: Suffix Pattern: <<TableName>>_Dim <<TableName>>_D Prefix … Continue reading Data Modeling – Dimension Table Effective Practices

What is DCL?

What is DCL (Data Control Language)? Data control language (DCL) is anything that is used for administrating access (permissions/security) to database content.  The main DCL commands are: Grant Revoke Related References Database Table Field Ordering Effective Practices Structured Query Language (SQL) Tuning What is DDL? What is DML?