| Structured Query Language | A descriptive computer language designed for updating, retrieving, and calculating data in table-based databases. |
| Database | A structured way to store lots of information. |
| Serialization | Take the information we have stored in memory and represent it as a series of characters/bytes that can be stored in a file. |
| Atomicity | Updates to the database allow for multiple changes to execute at once. Either all of them fail, or all of them succeed. |
| Consistency | Any rules the database enforces are applied when asking for changes. |
| Isolation | This allows for multiple database requests to be handled concurrently (e.g. reading and writing to multiple tables/rows at the same time). This feature is what allows databases to be a great choice for multi-user systems. |
| Durability | Ensures that once data is written to the database, the database does not lose the information in the case of a database, computer, or system crash. |
| SQL | a table-based storage paradigm, that stores data arranged in an Excel-like format, that focuses on normalizing our data by focusing on |
| relationships and structure. This is often referred to as "Relational Databases". | |
| NoSQL | Can be thought of as the opposite of SQL. At a high level, a NoSQL database stores data in a form other than the table structure.This looseness of data structure allows developers to more freely control what and how the data is stored. |
| Schema | The structure of a table that is represented by columns and constraints. |
| char(N) | The N represents the largest number of characters this column can store. If we supply less than N characters the rest of the column will be padded with spaces. This ensures the column is always N characters long. |
| varchar(N) | The N represents the largest number of characters the column can store, however, the width of the data is variable. If we supply less than N characters the column is not filled with spaces. |
| text | Allows for a variable number of characters, but has a much larger limit than what a char or varchar can support. In some cases many megabytes, or gigabytes of text. |
| smallint | Generally only used if disk space is at a premium. |
| integer | The common choice, as it offers the best balance between range, storage size, and performance. |
| bigint | Designed to be used when the range of the integer type is insufficient. |
| boolean | Stores a true or false value. |
| Date | Stores a year, month, and day together. Use YYYY-MM-DD format such as '2020-07-04' when adding data. |
| timestamp | Stores a precise time, Use YYYY-MM-DD HH:MM:DD format such as '2020-07-04 15:45:12 when adding data. |
| query | What we call the statements we ask a database to do for us, even if the statement's purpose is to create tables, or delete rows. |
| CREATE TABLE | Creating a table to store our information. This table will have rows (data) and columns (structure). (e.g. CREATE TABLE "Books" ("Title" TEXT NOT NULL, "PrimaryAuthor" TEXT, "YearPublished" INT,"Id" SERIAL PRIMARY KEY);) |
| ALTER TABLE | Modifying a table after the table has been created. (e.g. ALTER TABLE "Books" ADD COLUMN "Genre" VARCHAR(15);) |
| INSERT | To create a new row in our database. (e.g. INSERT INTO "TableName" ("ColumnA", "ColumnB", "ColumnC") VALUES ('columnAValue', 'columnBValue', 'columnCValue');) |
| SELECT | Statements that allow us to query and return a new view of the data. (e.g. SELECT "Title" FROM "Books";) |
| SELECT * | This query will give us back all the columns (*) from all the rows in the table. Regardless of how many rows there are. (e.g. SELECT * FROM "Books";) |
| WHERE | Filter down our table to only see rows that satisfy the conditions supplied. (e.g. SELECT "Title", "PrimaryAuthor" FROM "Books" WHERE "Genre" = 'horror';) |
| UPDATE | To change data in our database. (e.g. UPDATE "TableName" SET "ColumnA" = 'new value' WHERE "ColumnB" = 'some value';) |
| DELETE | To remove one or many rows from our database. (e.g. DELETE FROM "Books" WHERE "YearPublished" = 1995;) |
