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)
)