CREATE TABLE Locations(
	Id INT IDENTITY PRIMARY KEY,
	Latitude FLOAT ,
	Longitude FLOAT 
)

CREATE TABLE Credentials(
	Id INT IDENTITY PRIMARY KEY,
	Email VARCHAR(30) ,
	Password VARCHAR(20) 
)

CREATE TABLE Chats(
	Id INT IDENTITY PRIMARY KEY,
	Title VARCHAR(32) ,
	StartDate DATE ,
	IsActive BIT 
)

CREATE TABLE Users(
	Id INT IDENTITY PRIMARY KEY,
	Nickname VARCHAR(25) ,
	Gender CHAR(1) ,
	Age INT ,
	LocationId INT ,
	FOREIGN KEY (LocationId) REFERENCES Locations(Id),
	CredentialId INT UNIQUE,
	FOREIGN KEY (CredentialId) REFERENCES Credentials(Id)
)

CREATE TABLE Messages(
	Id INT IDENTITY PRIMARY KEY,
	Content VARCHAR(200) ,
	SentOn DATE ,
	ChatId INT ,
	FOREIGN KEY (ChatId) REFERENCES Chats(Id),
	UserId INT ,
	FOREIGN KEY (UserId) REFERENCES Users(id)
)

CREATE TABLE UsersChats(
	constraint PK_UsersChats
	primary key (ChatId, UserId),
	UserId INT ,
	FOREIGN KEY(UserId) REFERENCES Users(Id),
	ChatId INT ,
	FOREIGN KEY(ChatId) REFERENCES Chats(Id)
)